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A193940
Starting position of the first occurrence of the decimal number 10^n in the decimal expansion of Pi.
2
1, 49, 854, 854, 387791, 2393355, 10359802, 13310435, 172330849, 2542542101, 95257866194, 1587461837108, 3186699229889, 3186699229889
OFFSET
0,2
COMMENTS
From Dmitry Petukhov, Jan 15 2020: (Start)
Digits 3,1,4,1,5,... are indexed 0,1,2,3,4,...
10^2 without '0' after it found at 1816 position, but a(3)=854 < 1816, therefore a(2)=a(3)=854.
10^12 without '0' after it found at 6029081077667 position, but a(13)=3186699229889 < 6029081077667, therefore a(12)=a(13). (End)
EXAMPLE
Pi = 3.141592653589793238462643383279502884197169399375105.. The '1' (10^0) after the decimal point is at position 1. The '1' of the first occurrence of '10' (10^1) is at position 49.
MATHEMATICA
str = ToString[N[Pi-3, 2*10^8]]; s = "1"; Table[pos = StringPosition[str, s, 1][[1, 1]] - 2; s = s <> "0"; pos, {9}] (* this code takes a long time. T. D. Noe, Aug 10 2011 *)
CROSSREFS
KEYWORD
nonn,base,hard,more
AUTHOR
Kausthub Gudipati, Aug 10 2011
EXTENSIONS
Edited by Hans Havermann, Jul 21 2014
a(9) from Hans Havermann, Jul 21 2014
a(10)-a(13) from Dmitry Petukhov, Jan 15 2020
STATUS
approved