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%I #34 Jan 16 2020 02:03:22
%S 1,49,854,854,387791,2393355,10359802,13310435,172330849,2542542101,
%T 95257866194,1587461837108,3186699229889,3186699229889
%N Starting position of the first occurrence of the decimal number 10^n in the decimal expansion of Pi.
%C From _Dmitry Petukhov_, Jan 15 2020: (Start)
%C Digits 3,1,4,1,5,... are indexed 0,1,2,3,4,...
%C 10^2 without '0' after it found at 1816 position, but a(3)=854 < 1816, therefore a(2)=a(3)=854.
%C 10^12 without '0' after it found at 6029081077667 position, but a(13)=3186699229889 < 6029081077667, therefore a(12)=a(13). (End)
%H Peter Trüb, <a href="https://pi2e.ch/blog/2017/03/10/pi-digits-download/">22.4 trillion digits of pi</a>
%e 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.
%t 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 *)
%Y Cf. A000796, A176341, A194351.
%K nonn,base,hard,more
%O 0,2
%A _Kausthub Gudipati_, Aug 10 2011
%E Edited by _Hans Havermann_, Jul 21 2014
%E a(9) from _Hans Havermann_, Jul 21 2014
%E a(10)-a(13) from _Dmitry Petukhov_, Jan 15 2020
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