A326581 Odd integers which are prime or square.

1, 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 225, 227, 229, 233, 239, 241

Offset: 1

Author

Peter Luschny, Jul 15 2019

Keywords

• nonn

Comments

Contains for example 729=27^2 and hence differs from A062090. - R. J. Mathar, Jul 08 2025

Crossrefs

Cf. A065091, A000040, A016754, A000290, A326583.

Programs

Maple

s := n -> if irem(n, 2) = 1 and (isprime(n) or issqr(n)) then n else NULL fi:
seq(s(n), n=0..241);

Mathematica

Select[Range[1, 241, 2], Or[IntegerQ@ Sqrt@ #, PrimeQ@ #] &] (* Michael De Vlieger, Jul 15 2019 *)

Formula

Union of A065091 and A016754.