0,1

It is unknown whether Pi is a normal number. If it is (at least in base 10) then this sequence is well defined.

The numbers a(n) refer to the position of the initial digit of n in the decimal expansion of Pi, where "3" is at position a(3)=0, "1" is at position a(1)=1, etc. This is also the numbering scheme used on the "Pi search page" cited among the LINKS. See A232013 for a sequence based on iterations of this one. See A032445 for a variant of the present sequence, where numbering starts at one. - M. F. Hasler, Nov 16 2013

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Dave Andersen, Search within first 200,000,000 digits of pi.

Michael D. Huberty, Ko Hayashi & Chia Vang, First 100,000 digits of pi.

Simon Plouffe, First 50,000,000 digits of pi.

Index entries for sequences related to the number Pi.

a(n) = A032445(n)-1. - M. F. Hasler, Nov 16 2013

a(n) = 0 if n is in A011545, otherwise a(n) = A014777(n). - Pontus von Brömssen, Aug 31 2024

p=ToString[FromDigits[RealDigits[N[Pi, 10^4]][[1]]]]; Do[Print[StringPosition[p, ToString[n]][[1]][[1]] - 1], {n, 0, 100}] (* Vincenzo Librandi, Apr 17 2017 *)

With[{pid=RealDigits[Pi, 10, 800][[1]]}, Flatten[Table[ SequencePosition[ pid, IntegerDigits[n], 1], {n, 0, 70}], 1]][[All, 1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 27 2019 *)

(Python)

pi = "314159265358979323846264338327950288419716939937510582097494459230..."

[ pi.find(str(i)) for i in range(10000) ]

(PARI) A176341(n)=my(L=#Str(n)); n=Mod(n, 10^L); for(k=L-1, 9e9, Pi\.1^k-n||return(k+1-L)) \\ Make sure to use sufficient realprecision, e.g. via \p999. - M. F. Hasler, Nov 16 2013

Cf. A000796, A011545, A014777, A032445, A232013.

Sequence in context: A174923 A369651 A351809 * A134203 A014777 A303323

Adjacent sequences: A176338 A176339 A176340 * A176342 A176343 A176344

base,nonn,changed

Daniel E. Loeb, Apr 15 2010

approved