A007512 - OEIS

A007512

Primes of the form floor(e*10^k), i.e., formed by concatenation of an initial segment of the decimal expansion of e.
(Formerly M2184)

2, 271, 2718281, 2718281828459045235360287471352662497757247093699959574966967627724076630353547594571

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The number of digits in a(n) is given in A064118. This allows us to get larger terms that cannot be displayed here, via the given FORMULA. Sequences A005042, A072952, A115453, A119343, A210704, ... are the analogs for Pi, gamma, sqrt(2), sqrt(3), 3^(1/3), ... - M. F. Hasler, Aug 31 2013

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..4.

Eric Weisstein's World of Mathematics, e-Prime

Index entries related to "constant primes".

FORMULA

a(n) = floor(e*10^(A064118(n)-1)). - M. F. Hasler, Aug 31 2013

MAPLE

Digits := 110; n0 := evalf(E); for i from 1 to 100 do t1 := trunc(10^i*n0); if isprime(t1) then print(t1); fi; od:

PROG

(PARI) c=exp(1); for(k=0, precision(c), ispseudoprime(c\.1^k) & print1(c\.1^k, ", ")) \\ M. F. Hasler, Sep 01 2013

CROSSREFS

Sequence in context: A278771 A318171 A324596 * A048534 A135696 A008775

Adjacent sequences: A007509 A007510 A007511 * A007513 A007514 A007515

KEYWORD

base,nonn

AUTHOR

N. J. A. Sloane, Robert G. Wilson v, Simon Plouffe

EXTENSIONS

Next term is a 1781-digit BPSW-probable prime 2718281828459045235...211151368350627526023. - Randall L Rathbun, Feb 02 2002

Edited by T. D. Noe, Oct 30 2008

Edited by M. F. Hasler, Aug 31 2013

STATUS

approved