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

1,2

Comments

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

Links

Table of n, a(n) for n=1..60.

Formula

Union of A065091 and A016754.

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 *)

Crossrefs

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

Sequence in context: A238266 A308838 A080429 * A050150 A062090 A358975

Adjacent sequences: A326578 A326579 A326580 * A326582 A326583 A326584

Keyword

nonn

Author

Peter Luschny, Jul 15 2019

Status

approved