A113637 In the sequence of positive integers subtract 1 from each nonprime number.

0, 2, 3, 3, 5, 5, 7, 7, 8, 9, 11, 11, 13, 13, 14, 15, 17, 17, 19, 19, 20, 21, 23, 23, 24, 25, 26, 27, 29, 29, 31, 31, 32, 33, 34, 35, 37, 37, 38, 39, 41, 41, 43, 43, 44, 45, 47, 47, 48, 49, 50, 51, 53, 53, 54, 55, 56, 57, 59, 59, 61, 61, 62, 63, 64, 65, 67, 67, 68, 69, 71, 71, 73

Offset

1,2

Links

Table of n, a(n) for n=1..73.

Mathematica

Table[If[PrimeQ[n], n, n-1], {n, 73}] (* James C. McMahon, Jul 07 2024 *)

Prog

(PARI) a(n) = if (isprime(n), n, n-1); \\ Michel Marcus, Jul 08 2024

Crossrefs

Cf. A113636, A113638.

Sequence in context: A091937 A239906 A239907 * A257539 A159050 A363433

Adjacent sequences: A113634 A113635 A113636 * A113638 A113639 A113640

Keyword

easy,nonn

Author

Cino Hilliard, Jan 15 2006

Status

approved