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A083602
Starting positions of strings of four 1's in the decimal expansion of Pi.
1
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
1,1
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 *)
CROSSREFS
Cf. A050209 (three 1's), A083603 (five 1's).
Sequence in context: A254799 A254806 A253815 * A105655 A124411 A256809
KEYWORD
base,nonn
AUTHOR
Rick L. Shepherd, May 01 2003
STATUS
approved