A282973 Primes in A011546.

3, 31, 314159, 314159265359

Offset

1,1

Links

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

Eric Weisstein's World of Mathematics, Pi-Prime

Example

a(5) = A011546(1902) = 314159...066118631 is a prime with 1902 digits.
a(6) = A011546(3971) = 314159...411010447.
a(7) = A011546(5827) = 314159...690496521.
a(8) = A011546(16208) = A005042(5) = 314159....943936307.
For n<=17511, there are eight primes in sequence A011546(n).
In addition, because of round(Pi*10^47576) = floor(Pi*10^47576), and A011546(47577)(=A005042(6)) is a prime. Thus,  A011546(47577) will appear in here. A011546(613373)(=A005042(8)) as well. But A011546(78073)(=A005042(7)+1) is not prime.

Mathematica

Do[If[PrimeQ[Round[Pi*10^(n-1)]], Print[Round[Pi*10^(n-1)]]], {n, 17511}]
Select[Module[{nn=20, pid}, pid=RealDigits[Pi, 10, nn+2][[1]]; Table[Floor[(FromDigits[ Take[ pid, n+1]])/10+1/2], {n, nn}]], PrimeQ] (* Harvey P. Dale, Jan 01 2023 *)

Crossrefs

Cf. A011546, A282974, A000796, A005042.

Sequence in context: A276199 A118913 A297480 * A005042 A367038 A317482

Adjacent sequences: A282970 A282971 A282972 * A282974 A282975 A282976

Keyword

nonn,base

Author

XU Pingya, Feb 25 2017

Status

approved