cp's OEIS Frontend

A053746 Positions of '2's in the decimal expansion of Pi, where positions 1, 2, 3, ... correspond to digits 3, 1, 4, ...

%I A053746 #21 Jul 28 2024 11:05:48
%S A053746 7,17,22,29,34,54,64,74,77,84,90,94,103,113,115,136,137,141,150,161,
%T A053746 166,174,186,187,204,222,230,242,245,261,276,281,290,293,299,303,327,
%U A053746 330,334,336,338,355,375,381,407
%N A053746 Positions of '2's in the decimal expansion of Pi, where positions 1, 2, 3, ... correspond to digits 3, 1, 4, ...
%C A053746 See A037001 for the variant where digits 3, 1, 4, ... correspond to positions 0, 1, 2, ... - _M. F. Hasler_, Jul 28 2024
%H A053746 Vincenzo Librandi, <a href="/A053746/b053746.txt">Table of n, a(n) for n = 1..1000</a>
%H A053746 <a href="/index/Ph#Pi314">Index entries for sequences related to the number Pi</a>
%F A053746 a(n) = A037001(n) + 1. - _Georg Fischer_, May 31 2021
%e A053746 Pi = 3.1415926... where the first '2' occurs as the 7th digit.
%t A053746 Flatten[Position[RealDigits[Pi, 10, 1000][[1]], 2]] (* _Vincenzo Librandi_, Oct 07 2013 *)
%o A053746 (PARI) A053746_upto(N=999)={localprec(N+20); select(d->d==2, digits(Pi\10^-N), 1)} \\ _M. F. Hasler_, Jul 28 2024
%Y A053746 Cf. A000796 (decimal expansion (or digits) of Pi).
%Y A053746 Cf. A037001 (= a(n) - 1: the same with different offset).
%Y A053746 Cf. A053745 - A053753 (similar for digits 1 through 9).
%Y A053746 Cf. A035117 (first occurrence of at least n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
%Y A053746 Cf. A096755 (first occurrence of exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
%Y A053746 Cf. A121280 = A068987 - 1: position of "123...n" in Pi's decimals.
%Y A053746 Cf. A176341: first occurrence of n in Pi's digits.
%Y A053746 Cf. A088566 (primes in this sequence).
%K A053746 nonn,base
%O A053746 1,1
%A A053746 _Simon Plouffe_, Feb 20 2000
%E A053746 Changed offset from 0 to 1 by _Vincenzo Librandi_, Oct 07 2013