A083602 Starting positions of strings of four 1's in the decimal expansion of Pi.

12700, 16732, 32788, 32789, 37230, 43154, 48665, 55716, 87323, 91195, 92410, 93535, 120459, 120460, 123036, 123954, 140159, 141899, 141900, 145690, 149927, 159573, 172049, 175018, 191909, 209140, 215209, 248918, 255945, 255946, 255947

Offset: 1

Author

Rick L. Shepherd, May 01 2003

Keywords

• base
• nonn

Links

• Dave Andersen, Pi-Search Page
• Eric Weisstein's World of Mathematics, Pi Digits.
• Index entries for sequences related to the number Pi

Crossrefs

Cf. A050209 (three 1's), A083603 (five 1's).

Programs

Mathematica

$MaxPrecision=10^8;a=RealDigits[Pi,10,3*9! ];lst={};Do[b=a[[1]][[n]];c=a[[1]][[n+1]];d=a[[1]][[n+2]];e=a[[1]][[n+3]];If[b==1&&c==1&&d==1&&e==1,AppendTo[lst,n-1]],{n,7!,3*9!-3}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 07 2009 *)
a=RealDigits[Pi,10,9! ];lst={};Do[b=a[[1]][[n]];c=a[[1]][[n+1]];d=a[[1]][[n+2]];e=a[[1]][[n+3]];If[b==1&&c==1&&d==1&&e==1,AppendTo[lst,n-1]],{n,9!-5}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 05 2009 *)
Flatten[Position[Partition[RealDigits[Pi,10,260000][[1]],4,1], ?(#=={1,1,1,1}&)]-1]  (* _Harvey P. Dale, Apr 21 2011 *)
SequencePosition[RealDigits[Pi,10,256000][[1]],{1,1,1,1}][[All,1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 26 2020 *)