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Search: a001204 -id:a001204
Displaying 1-5 of 5 results found. page 1
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A003417 Continued fraction for e.
(Formerly M0088) 		+10
37
2, 1, 2, 1, 1, 4, 1, 1, 6, 1, 1, 8, 1, 1, 10, 1, 1, 12, 1, 1, 14, 1, 1, 16, 1, 1, 18, 1, 1, 20, 1, 1, 22, 1, 1, 24, 1, 1, 26, 1, 1, 28, 1, 1, 30, 1, 1, 32, 1, 1, 34, 1, 1, 36, 1, 1, 38, 1, 1, 40, 1, 1, 42, 1, 1, 44, 1, 1, 46, 1, 1, 48, 1, 1, 50, 1, 1, 52, 1, 1, 54, 1, 1, 56, 1, 1, 58, 1, 1, 60, 1, 1, 62, 1, 1, 64, 1, 1, 66 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
This is also the Engel expansion for 3*exp(1/2)/2 - 1/2. - Gerald McGarvey, Aug 07 2004
Sorted with duplicate terms dropped, this is A004277, 1 together with the positive even numbers. - Alonso del Arte, Jan 27 2012
From Peter Bala, Nov 26 2019: (Start)
Related continued fractions expansions:
2*e = [5; 2, 3, 2, 3, 1, 2, 1, 3, 4, 3, 1, 4, 1, 3, 6, 3, 1, 6, ..., 1, 3, 2*n, 3, 1, 2*n, ...].
(1/2)*e = [1; 2, 1, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 3, 5, 3, 1, 5, 1, 3, 7, 3, 1, 7, ..., 1, 3, 2*n + 1, 3, 1, 2*n + 1, ...].
4*e = [10, 1, 6, 1, 7, 2, 7, 2, 7, 1, 1, 1, 7, 3, 7, 1, 2, 1, 7, 4, 7, 1, 3, 1, 7, 5, 7, 1, 4, ..., 1, 7, n+1, 7, 1, n, ...].
(1/4)*e = [0, 1, 2, 8, 3, 1, 1, 1, 1, 7, 1, 1, 2, 1, 1, 1, 2, 7, 1, 2, 2, 1, 1, 1, 3, 7, 1, 3, 2, 1, 1, 1, 4, 7, 1, 4, 2, ..., 1, 1, 1, n, 7, 1, n, 2, ...]. (End)
REFERENCES
CRC Standard Mathematical Tables and Formulae, 30th ed. 1996, p. 88.
S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 1.3.2.
J. R. Goldman, The Queen of Mathematics, 1998, p. 70.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 0..9999
Thomas Baruchel and C. Elsner, On error sums formed by rational approximations with split denominators, arXiv preprint arXiv:1602.06445 [math.NT], 2016.
H. Cohn, A short proof of the simple continued fraction expansion of e, Amer. Math. Monthly, 113 (No. 1, 2006), 57-62. [JSTOR] and arXiv:math/0601660 [math.NT], 2006.
S. Crowley, Mellin and Laplace Integral Transforms Related to the Harmonic Sawtooth Map and a Diversion Into The Theory Of Fractal Strings, vixra:1202.0079 v2, 2012.
Francesco Dolce and Pierre-Adrien Tahay, Column representation of Sturmian words in cellular automata, Czech Technical University (Prague, Czechia, 2022).
W. R. Harmon, Letter to N. J. A. Sloane, Sep 1974
MathOverflow, What is the effect of adding 1/2 to a continued fraction?
K. Matthews, Finding the continued fraction of e^(l/m)
Sophie Morier-Genoud and Valentin Ovsienko, On q-deformed real numbers, arXiv:1908.04365 [math.QA], 2019.
C. D. Olds, The simple continued fraction expansion of e, Am. Math. Monthly 77 (9) (1970) 968-974.
T. J. Osler, A proof of the continued fraction expansion of e^(1/M), Amer. Math. Monthly, 113 (No. 1, 2006), 62-66.
Oskar Perron, Die Lehre von den Kettenbrüchen, 2nd ed., Teubner, Leipzig, 1929, p. 134.
Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009.
Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 1992
Ward. O. Whitt, Weirdness in CTMC's, Notes for Course IEOR 6711: Stochastic Models I, [PDF], 2012. - From N. J. A. Sloane, Jan 03 2013
Eric Weisstein's World of Mathematics, e Continued Fraction
Gang Xiao, Contfrac
Index entries for continued fractions for constants
Index entries for linear recurrences with constant coefficients, signature (0,0,2,0,0,-1).
FORMULA
From Paul Barry, Jun 27 2006: (Start)
G.f.: (2 + x + 2*x^2 - 3*x^3 - x^4 + x^6)/(1 - 2*x^3 + x^6).
a(n) = 0^n + Sum{k = 0..n} 2*sin(2*Pi*(k - 1)/3)*floor((2*k - 1)/3)/sqrt(3). [Corrected and simplified by Jianing Song, Jan 05 2019] (End)
a(n) = 2*a(n-3) - a(n-6), n >= 7. - Philippe Deléham, Feb 10 2009
G.f.: 1 + U(0) where U(k)= 1 + x/(1 - x*(2*k + 1)/(1 + x*(2*k + 1) - 1/((2*k + 1) + 1 - (2*k + 1)*x/(x + 1/U(k+1))))); (continued fraction, 5-step). - Sergei N. Gladkovskii, Oct 07 2012
a(3*n-1) = 2*n, a(0) = 2, a(n) = 1 otherwise (i.e., for n+1 > 1, not a multiple of 3). - M. F. Hasler, May 01 2013
E.g.f.: First derivative of (2/9)*exp(x)*(x + 3) + (2/9)*exp(-x/2)*(2*x*cos((sqrt(3)/2)*x+2*Pi/3) - 3*cos((sqrt(3)/2)*x)) + x. - Jianing Song, Jan 05 2019
EXAMPLE
2.718281828459... = 2 + 1/(1 + 1/(2 + 1/(1 + 1/(1 + ...))))
MAPLE
numtheory[cfrac](exp(1), 100, 'quotients'); # Jani Melik, May 25 2006
A003417:=(2+z+2*z**2-3*z**3-z**4+z**6)/(z-1)**2/(z**2+z+1)**2; # Simon Plouffe in his 1992 dissertation
MATHEMATICA
ContinuedFraction[E, 100] (* Stefan Steinerberger, Apr 07 2006 *)
a[n_] := KroneckerDelta[1, n] + 2 n/3 - (2 n - 3)/3 DirichletCharacter[3, 1, n]; Table[a[n], {n, 1, 20}] (* Enrique Pérez Herrero, Feb 23 2013 *)
Table[Piecewise[{{2, n == 0}, {2 (n + 1)/3, Mod[n, 3] == 2}}, 1], {n, 0, 120}] (* Eric W. Weisstein, Jan 05 2019 *)
Join[{2}, LinearRecurrence[{0, 0, 2, 0, 0, -1}, {1, 2, 1, 1, 4, 1}, 120]] (* Eric W. Weisstein, Jan 05 2019 *)
Join[{2}, Table[(2 (n + 4) + (1 - 2 n) Cos[2 n Pi/3] + Sqrt[3] (1 - 2 n) Sin[2 n Pi/3])/9, {n, 120}]] (* Eric W. Weisstein, Jan 05 2019 *)
Join[{2}, Flatten[Table[{1, 2n, 1}, {n, 40}]]] (* Harvey P. Dale, Jan 21 2020 *)
PROG
(PARI) contfrac(exp(1)) \\ Alexander R. Povolotsky, Feb 23 2008
(PARI) { allocatemem(932245000); default(realprecision, 25000); x=contfrac(exp(1)); for (n=1, 10000, write("b003417.txt", n-1, " ", x[n])); } \\ Harry J. Smith, Apr 14 2009
(PARI) A003417(n)=if(n%3<>2, 1+(n==0), (n+1)/3*2) \\ M. F. Hasler, May 01 2013
(Scala) def eContFracTrio(n: Int): List[Int] = List(1, 2 * n, 1)
2 +: ((1 to 40).map(eContFracTrio).flatten) // Alonso del Arte, Nov 22 2020, with thanks to Harvey P. Dale
(Python)
def A003417(n): return 2 if n == 0 else 1 if n % 3 != 2 else (n+1)//3<<1 # Chai Wah Wu, Jul 27 2022
CROSSREFS
Cf. A001113, A007676, A007677, A001204, A058282, A005131.
Cf. A006083, A006084, A006085, A081750.
Run lengths of A342991.
KEYWORD
nonn,cofr,nice,easy
AUTHOR
N. J. A. Sloane
EXTENSIONS
Offset changed by Andrew Howroyd, Aug 07 2024
STATUS
approved
A072334 Decimal expansion of e^2. +10
33
7, 3, 8, 9, 0, 5, 6, 0, 9, 8, 9, 3, 0, 6, 5, 0, 2, 2, 7, 2, 3, 0, 4, 2, 7, 4, 6, 0, 5, 7, 5, 0, 0, 7, 8, 1, 3, 1, 8, 0, 3, 1, 5, 5, 7, 0, 5, 5, 1, 8, 4, 7, 3, 2, 4, 0, 8, 7, 1, 2, 7, 8, 2, 2, 5, 2, 2, 5, 7, 3, 7, 9, 6, 0, 7, 9, 0, 5, 7, 7, 6, 3, 3, 8, 4, 3, 1, 2, 4, 8, 5, 0, 7, 9, 1, 2, 1, 7, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Also where x^(1/sqrt(x)) is a maximum. - Robert G. Wilson v, Oct 22 2014
REFERENCES
Ovidiu Furdui, Limits, Series, and Fractional Part Integrals: Problems in Mathematical Analysis, New York: Springer, 2013. See Problem 1.4, pages 2 and 28-29.
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..20000
John Cosgrave, e^2 is irrational.
Index entries for transcendental numbers.
FORMULA
Equals Sum_{n>=0} Sum_{k>=0} 1/(n!*k!). - Fredrik Johansson, Apr 21 2006
Equals Sum_{n>=0} 2^n/n!. - Daniel Hoyt Nov 20 2020
From Peter Bala, Jan 13 2022: (Start)
e^2 = Sum_{n >= 0} 2^n/n!. Faster converging series include
e^2 = 8*Sum_{n >= 0} 2^n/(p(n-1)*p(n)*n!), where p(n) = n^2 - n + 2 and
e^2 = -48*Sum_{n >= 0} 2^n/(q(n-1)*q(n)*n!), where q(n) = n^3 + 5*n - 2.
e^2 = 7 + Sum_{n >= 0} 2^(n+3)/((n+2)^2*(n+3)^2*n!) and
7/e^2 = 1 - Sum_{n >= 0} (-2)^(n+1)*n^2/(n+2)!.
e^2 = 7 + 2/(5 + 1/(7 + 1/(9 + 1/(11 + ...)))) (follows from the fact that A004273 is the continued fraction expansion of tanh(1) = (e^2 - 1)/ (e^2 + 1)). Cf. A001204. (End)
Equals lim_{n->oo} (Sum_{k=1..n} 1/binomial(n,k)^x)^(n^x), for all real x > 1/2 (Furdui, 2013). - Amiram Eldar, Mar 26 2022
EXAMPLE
7.389056098930650...
MATHEMATICA
RealDigits[E^2, 10, 100][[1]] (* Vincenzo Librandi, Apr 05 2020 *)
PROG
(PARI) default(realprecision, 20080); x=exp(2); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b072334.txt", n, " ", d)); \\ Harry J. Smith, Apr 30 2009
(Magma) SetDefaultRealField(RealField(100)); Exp(1)^2; // Vincenzo Librandi, Apr 05 2020
CROSSREFS
Cf. A001204 (continued fraction).
Cf. A001113, A091933, A092426, A092511, A092512, A092513.
KEYWORD
nonn,cons
AUTHOR
N. J. A. Sloane, Jul 15 2002
STATUS
approved
A058282 Continued fraction for e^3. +10
4
20, 11, 1, 2, 4, 3, 1, 5, 1, 2, 16, 1, 1, 16, 2, 13, 14, 4, 6, 2, 1, 1, 2, 2, 2, 3, 5, 1, 3, 1, 1, 68, 7, 5, 1, 4, 2, 1, 1, 1, 1, 1, 1, 7, 3, 1, 6, 1, 2, 5, 4, 7, 2, 1, 3, 2, 2, 1, 2, 1, 4, 1, 1, 13, 1, 1, 2, 1, 1, 1, 1, 3, 7, 11, 18, 54, 1, 2, 2, 2, 1, 1, 6, 2, 2, 46, 2, 189, 1, 24, 1, 8, 13, 4, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..20000
K. Matthews, Finding the continued fraction of e^(l/m) ["... there is no known formula for the partial quotients of the continued fraction expansion of e^3, or more generally e^(l/m) with l distinct from 1,2 and gcd(l,m)=1..."]
G. Xiao, Contfrac
Index entries for continued fractions for constants
EXAMPLE
20.085536923187667740928529... = 20 + 1/(11 + 1/(1 + 1/(2 + 1/(4 + ...)))). - Harry J. Smith, Apr 30 2009
MAPLE
with(numtheory); Digits:=200: cf:=convert(evalf( exp(3)), confrac); # N. J. A. Sloane, Sep 05 2012
MATHEMATICA
ContinuedFraction[ E^3, 100]
PROG
(PARI) contfrac(exp(1)^3)
(PARI) { allocatemem(932245000); default(realprecision, 21000); x=contfrac(exp(3)); for (n=1, 20001, write("b058282.txt", n-1, " ", x[n])); } \\ Harry J. Smith, Apr 30 2009
CROSSREFS
Cf. A001204, A003417, A005131.
KEYWORD
cofr,nonn,easy
AUTHOR
Robert G. Wilson v, Dec 07 2000
EXTENSIONS
More terms from Jason Earls, Jul 10 2001
STATUS
approved
A159824 Continued fraction for Pi^Pi (cf. A073233). +10
1
36, 2, 6, 9, 2, 1, 2, 5, 1, 1, 6, 2, 1, 291, 1, 38, 50, 1, 2, 5, 4, 1, 2, 2, 1, 5, 1, 4, 13, 2, 1, 4, 3, 3, 1, 2, 25, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 3, 1, 43, 1, 2, 7, 3, 1, 1, 1, 2, 4, 2, 1, 1, 3, 1, 3, 3, 2, 2, 16, 3, 5, 2, 1, 5, 2, 1, 10, 1, 1, 3, 1, 13, 1, 1, 3, 1, 10, 4, 1, 1, 1, 38, 1, 2, 2, 1, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..20000
EXAMPLE
36.4621596072079117709908260... = 36 + 1/(2 + 1/(6 + 1/(9 + 1/(2 + ...)))).
MATHEMATICA
ContinuedFraction[Pi^Pi, 200] (* Vladimir Joseph Stephan Orlovsky, Jul 20 2010 *)
PROG
(PARI) { allocatemem(932245000); default(realprecision, 21000); x=contfrac(Pi^Pi); for (n=1, 20001, write("b159824.txt", n-1, " ", x[n])); }
CROSSREFS
Cf. A001076, A001203, A001204, A002945, A010767, A011002, A011003, A073233, A073238, A179613, A179615, A179616, A179617.
KEYWORD
nonn
AUTHOR
Harry J. Smith, Apr 30 2009
EXTENSIONS
Edited by N. J. A. Sloane, Jul 22 2010
STATUS
approved
A322506 Factorial expansion of 1/exp(2) = Sum_{n>=1} a(n)/n!. +10
0
0, 0, 0, 3, 1, 1, 3, 0, 6, 4, 7, 5, 2, 9, 9, 8, 10, 8, 9, 1, 13, 18, 1, 2, 8, 15, 26, 10, 22, 1, 18, 9, 20, 10, 2, 6, 13, 19, 16, 38, 38, 3, 32, 5, 39, 24, 7, 27, 14, 41, 20, 39, 32, 7, 20, 35, 44, 50, 24, 34, 51, 14, 39, 47, 49, 15, 61, 54, 60, 52, 34, 60, 32, 72, 48, 12, 67, 52, 22, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
Table of n, a(n) for n=1..80.
Index entries for factorial base representation
EXAMPLE
1/exp(2) = 0 + 0/2! + 0/3! + 3/4! + 1/5! + 1/6! + 3/7! + 0/8! + 6/9! +...
MATHEMATICA
With[{b = 1/E^2}, Table[If[n == 1, Floor[b], Floor[n!*b] - n*Floor[(n - 1)!*b]], {n, 1, 100}]]
PROG
(PARI) default(realprecision, 250); b = exp(-2); for(n=1, 80, print1(if(n==1, floor(b), floor(n!*b) - n*floor((n-1)!*b)), ", "))
(Magma) SetDefaultRealField(RealField(250)); [Floor(Exp(-2))] cat [Floor(Factorial(n)*Exp(-2)) - n*Floor(Factorial((n-1))*Exp(-2)) : n in [2..80]];
(Sage)
b=exp(-2);
def a(n):
if (n==1): return floor(b)
else: return expand(floor(factorial(n)*b) -n*floor(factorial(n-1)*b))
[a(n) for n in (1..80)]
CROSSREFS
Cf. A092553 (decimal expansion), 0 U A001204 (continued fraction).
Cf. A054977 (e), A067840 (e^2), A068453 (sqrt(e)), A237420 (1/e).
KEYWORD
nonn
AUTHOR
G. C. Greubel, Dec 12 2018
STATUS
approved
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Last modified August 29 15:31 EDT 2024. Contains 375517 sequences. (Running on oeis4.)