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A037007 Positions of the digit '9' in the decimal expansion of Pi, where positions 0, 1, 2,... correspond to digits 3, 1, 4, ....

%I A037007 #30 Feb 16 2025 08:32:37
%S A037007 5,12,14,30,38,42,44,45,55,58,62,79,80,100,122,129,144,169,180,187,
%T A037007 190,193,199,208,214,247,249,259,284,294,328,331,336,341,353,356,388,
%U A037007 391,399,414,416,418,422,433,440,459,460,465,482,487,496,498,501,527
%N A037007 Positions of the digit '9' in the decimal expansion of Pi, where positions 0, 1, 2,... correspond to digits 3, 1, 4, ....
%C A037007 Primes in this sequence are 5, 79, 193, 199, 331, 353, 433, 487, 941, ... - _M. F. Hasler_, Jul 29 2024
%H A037007 Amiram Eldar, <a href="/A037007/b037007.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..369 from M. F. Hasler)
%H A037007 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PiDigits.html">Pi Digits.</a>
%H A037007 <a href="/index/Ph#Pi314">Index entries for sequences related to the number Pi</a>
%F A037007 a(n) = A053753(n) - 1. - _M. F. Hasler_, Mar 20 2017
%F A037007 a(n) ~ 10*n if Pi is normal (as generally assumed, but yet unproved). - _M. F. Hasler_, Jul 29 2024
%e A037007 The first digit '9' occurs in 3.1415926... at the 5th place after the decimal point, whence a(1) = 5.
%t A037007 Flatten @ Position[ RealDigits[Pi - 3, 10, 500][[1]], 9] (* _Robert G. Wilson v_, Mar 07 2011 *)
%o A037007 (PARI) A037007_upto(N=999, d=9)={localprec(N+20); [i-1|i<-[1..#N=digits(Pi\10^-N)], N[i]==d]} \\ _M. F. Hasler_, Jul 29 2024
%Y A037007 Cf. A000796 (decimals of Pi).
%Y A037007 Cf. A053753 (variant with all values increased by 1).
%Y A037007 Cf. A037000, A037001, A037002, A037003, A037004, A037005, A036974, A037006, A037008 (similar for digits 1, ..., 8 and 0).
%Y A037007 Cf. A048940, A096763 (starting position of at least/exactly n '9's).
%K A037007 nonn,base
%O A037007 1,1
%A A037007 Nicolau C. Saldanha (nicolau(AT)mat.puc-rio.br)