[go: up one dir, main page]

login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
Revision History for A263015 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A263015 Integers n such that A007504(n) is the sum of 2 nonzero squares.
(history; published version)
#23 by N. J. A. Sloane at Sat Nov 28 19:16:15 EST 2015
STATUS

proposed

approved

#22 by Altug Alkan at Fri Nov 27 07:22:09 EST 2015
STATUS

editing

proposed

#21 by Altug Alkan at Fri Nov 27 07:16:17 EST 2015
COMMENTS

Integers n such that sum of the first n primes is the sum of 2 nonzero squares. Initial values of corresponding sum of first n primes are 2, 5, 10, 17, 41, 58, 100, 160, 197 and 281.

Initial values of corresponding sum of first n primes are 2, 5, 10, 17, 41, 58, 100, 160, 197 and 281.

#20 by Altug Alkan at Fri Nov 27 07:12:00 EST 2015
NAME

allocatedIntegers n such that A007504(n) is the sum of for2 Altugnonzero Alkansquares.

DATA

1, 2, 3, 4, 6, 7, 9, 11, 12, 14, 15, 21, 25, 29, 35, 55, 58, 59, 64, 71, 85, 89, 93, 94, 95, 100, 101, 102, 108, 112, 114, 116, 122, 124, 130, 131, 133, 135, 141, 146, 147, 151, 159, 162, 165, 170, 171, 172, 177, 178, 183, 190, 192, 193, 194, 204, 205, 206

OFFSET

1,2

COMMENTS

Integers n such that sum of the first n primes is the sum of 2 nonzero squares. Initial values of corresponding sum of first n primes are 2, 5, 10, 17, 41, 58, 100, 160, 197 and 281.

EXAMPLE

a(3) = 3 because 2 + 3 + 5 = 3^2 + 1^2.

a(5) = 6 because 2 + 3 + 5 + 7 + 11 + 13 = 5^2 + 4^2.

a(6) = 7 because 2 + 3 + 5 + 7 + 11 + 13 + 17 = 7^2 + 3^2.

PROG

(PARI) a(n) = sum(k=1, n, prime(k));

is(n) = { for( i=1, #n=factor(n)~%4, n[1, i]==3 && n[2, i]%2 && return); n && ( vecmin(n[1, ])==1 || (n[1, 1]==2 && n[2, 1]%2)) }

for(n=1, 1e3, if(is((a(n))), print1(n, ", ")))

CROSSREFS

Cf. A000404, A007504.

KEYWORD

allocated

nonn

AUTHOR

Altug Alkan, Nov 27 2015

STATUS

approved

editing

#19 by Altug Alkan at Fri Nov 27 07:12:00 EST 2015
NAME

allocated for Altug Alkan

KEYWORD

recycled

allocated

#18 by N. J. A. Sloane at Fri Nov 27 00:12:36 EST 2015
STATUS

editing

approved

#17 by N. J. A. Sloane at Fri Nov 27 00:12:32 EST 2015
NAME

Numbers n such that A263014(n)=0.

DATA

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95

OFFSET

1,2

COMMENTS

Complement of A263016.

MATHEMATICA

Sp[n_, k_] := Mod[Sum[If[GCD[a^2 + b^2, n] == 1, PowerMod[(a + b I), k, n], 0], {a, n}, {b, n}], n]; Select[Range[100], Sp[#, #] == 0 &]

CROSSREFS

Cf. A263014, A263016.

KEYWORD

nonn

recycled

AUTHOR

José María Grau Ribas, Oct 07 2015

STATUS

proposed

editing

#16 by Michel Marcus at Wed Oct 14 15:18:52 EDT 2015
STATUS

editing

proposed

Discussion
Fri Nov 27 00:12
N. J. A. Sloane: I don' think this deserves its own sequence - a sequence that starts 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 has to be pretty important to get included! Will recycle.
#15 by Michel Marcus at Wed Oct 14 15:18:47 EDT 2015
COMMENTS

complementComplement of A263016.

STATUS

proposed

editing

#14 by José María Grau Ribas at Wed Oct 14 13:31:55 EDT 2015
STATUS

editing

proposed

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 29 18:55 EDT 2024. Contains 375518 sequences. (Running on oeis4.)