

A060421


Numbers n such that the first n digits of the decimal expansion of Pi form a prime.


13




OFFSET

1,2


COMMENTS

The Brown link states that in 2001 Ed T. Prothro reported discovering that 16208 gives a probable prime and that Prothro verified that all values for 500 through 16207 digits of Pi are composites.  Rick L. Shepherd, Sep 10 2002
The corresponding primes are in A005042.  Alexander R. Povolotsky, Dec 17 2007


LINKS

Table of n, a(n) for n=1..8.
K. S. Brown, Primes in the Decimal Expansion of Pi [Broken link?]
K. S. Brown, Primes in the Decimal Expansion of Pi [Cached copy]
Prime Curios, 314159
Prime Curios, 31415...36307 (16208digits)
Eric Weisstein's World of Mathematics, Constant Primes
Eric Weisstein's World of Mathematics, Integer Sequence Primes
Eric Weisstein's World of Mathematics, Pi Digits
Eric Weisstein's World of Mathematics, PiPrime


EXAMPLE

3 is prime, so a(1) = 1; 31 is prime, so a(2) = 2; 314159 is prime, so a(3) = 6; ...


MATHEMATICA

Do[If[PrimeQ[FromDigits[RealDigits[N[Pi, n + 10], 10, n][[1]]]], Print[n]], {n, 1, 9016} ]


CROSSREFS

Cf. A000796 (Pi), A005042, A007523, A047658.
Primes in other constants: A064118 (e), A065815 (gamma), A064119 (phi), A118328 (Catalan's constant), A115377 (sqrt(2)), A119344 (sqrt(3)), A228226 (log 2), A228240 (log 10), A119334 (zeta(3)), A122422 (Soldner's constant), A118420 (GlaisherKinkelin constant), A174974 (GolombDickman constant), A118327 (Khinchin's constant).
Sequence in context: A005530 A072191 A118324 * A054970 A211348 A295912
Adjacent sequences: A060418 A060419 A060420 * A060422 A060423 A060424


KEYWORD

hard,nonn,base


AUTHOR

Michel ten Voorde, Apr 05 2001


EXTENSIONS

a(6) = 47577 from Eric W. Weisstein, Apr 01 2006
a(7) = 78073 from Eric W. Weisstein, Jul 13 2006
a(8) = 613373 from Adrian Bondrescu, May 29 2016


STATUS

approved



