A153031 Positions of prime digits of Pi.

1, 5, 7, 9, 10, 11, 14, 16, 17, 18, 22, 25, 26, 28, 29, 30, 32, 34, 40, 44, 47, 48, 49, 52, 54, 57, 62, 64, 65, 67, 74, 77, 84, 87, 90, 91, 92, 94, 97, 100, 103, 110, 112, 113, 115, 116, 121, 124, 131, 132, 134, 136, 137, 138, 140, 141, 142, 143, 144, 150, 157, 159, 161

Offset

1,2

Links

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Formula

a(n) = A073303(n) + 1. - Michel Marcus, May 29 2014

Mathematica

Flatten[Position[ Map[If[PrimeQ[ # ], "*", # ] &, RealDigits[ N[Pi, 100]][[1]]], "*"]]
Select[ Range@ 166, PrimeQ[ RealDigits[Pi, 10, 166][[1, # ]]] &] (* Robert G. Wilson v, Dec 21 2008 *)
Flatten[Position[RealDigits[Pi, 10, 200][[1]], _?PrimeQ]] (* Harvey P. Dale, Mar 22 2015 *)

Prog

(PARI) \p 1000
p=Vec(Str(Pi/10)); for(n=1, #p-9, if(isprime(eval(p[n+2])), print1(n", "))) \\ Jens Kruse Andersen, Jul 23 2014

Crossrefs

Cf. A000796.

Sequence in context: A079696 A275718 A129270 * A334303 A184110 A138892

Adjacent sequences: A153028 A153029 A153030 * A153032 A153033 A153034

Keyword

nonn,base

Author

Julio Cesar de la Yncera, Dec 17 2008

Extensions

More concise Mathematica coding added and sequence extended by Robert G. Wilson v, Dec 21 2008

Status

approved