A050209 Starting positions of strings of 3 1's in the decimal expansion of Pi.

153, 983, 3503, 3992, 4508, 6116, 6803, 6963, 8366, 11730, 12527, 12611, 12700, 12701, 13597, 14375, 15190, 16732, 16733, 19627, 22270, 22897, 23208, 23244, 23660, 25205, 25448, 25752, 27053, 29492, 29687, 29810, 31281, 31488, 32498

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn
• base

Comments

The "position" is the number of digits to the right of the decimal point. - Harvey P. Dale, Jan 02 2019

Links

• Eric Weisstein's World of Mathematics, Pi Digits
• Index entries for sequences related to the number Pi

Crossrefs

Cf. A000796.

Programs

Maple

Pidigs:= convert(evalf[40000](Pi),string):
StringTools[SearchAll]("111",Pidigs[3..-1]); # Robert Israel, Jan 09 2015

Mathematica

a=RealDigits[Pi,10,9! ];lst={};Do[b=a[[1]][[n]];c=a[[1]][[n+1]];d=a[[1]][[n+2]];If[b==1&&c==1&&d==1,AppendTo[lst,n-1]],{n,9!-2}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 02 2009 *)
SequencePosition[RealDigits[Pi,10,33000][[1]],{1,1,1}][[All,1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 02 2019 *)