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

7, 17, 22, 29, 34, 54, 64, 74, 77, 84, 90, 94, 103, 113, 115, 136, 137, 141, 150, 161, 166, 174, 186, 187, 204, 222, 230, 242, 245, 261, 276, 281, 290, 293, 299, 303, 327, 330, 334, 336, 338, 355, 375, 381, 407

Offset: 1

Author

Simon Plouffe, Feb 20 2000

Keywords

• nonn
• base

Comments

See A037001 for the variant where digits 3, 1, 4, ... correspond to positions 0, 1, 2, ... - M. F. Hasler, Jul 28 2024

Examples

			Pi = 3.1415926... where the first '2' occurs as the 7th digit.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index entries for sequences related to the number Pi

Crossrefs

Cf. A000796 (decimal expansion (or digits) of Pi).

Cf. A037001 (= a(n) - 1: the same with different offset).

Cf. A053745 - A053753 (similar for digits 1 through 9).

Cf. A035117 (first occurrence of at least n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).

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).

Cf. A121280 = A068987 - 1: position of "123...n" in Pi's decimals.

Cf. A176341: first occurrence of n in Pi's digits.

Cf. A088566 (primes in this sequence).

Programs

Mathematica

Flatten[Position[RealDigits[Pi, 10, 1000][[1]], 2]] (* Vincenzo Librandi, Oct 07 2013 *)

PARI

A053746_upto(N=999)={localprec(N+20); select(d->d==2, digits(Pi\10^-N), 1)} \\ M. F. Hasler, Jul 28 2024

Formula

a(n) = A037001(n) + 1. - Georg Fischer, May 31 2021

Extensions

Changed offset from 0 to 1 by Vincenzo Librandi, Oct 07 2013