A354144 Prime powers together with semiprimes.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 43, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 64, 65, 67, 69, 71, 73, 74, 77, 79, 81, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103, 106, 107, 109, 111, 113, 115, 118, 119, 121, 122, 123, 125, 127, 128, 129, 131, 133, 134, 137

Offset: 1

Author

N. J. A. Sloane, May 20 2022

Keywords

• nonn

Comments

Union of A000961 and A001358.

Although this is 1 together with A102466, it has arisen sufficiently often that it deserves its own entry.

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000961, A001221, A001222, A001358, A102466.

Programs

Maple

isPPorSP := proc(n) if n=1 or nops(numtheory[factorset](n)) = 1 or numtheory[bigomega](n) = 2 then 'true' else 'false'; fi; end;