A359771 Union of even numbers with an odd number of prime factors and odd numbers with an even number of prime factors, when the number of prime factors is counted with multiplicity.

1, 2, 8, 9, 12, 15, 18, 20, 21, 25, 28, 30, 32, 33, 35, 39, 42, 44, 48, 49, 50, 51, 52, 55, 57, 65, 66, 68, 69, 70, 72, 76, 77, 78, 80, 81, 85, 87, 91, 92, 93, 95, 98, 102, 108, 110, 111, 112, 114, 115, 116, 119, 120, 121, 123, 124, 128, 129, 130, 133, 135, 138, 141, 143, 145, 148, 154, 155, 159, 161

Offset: 1

Author

Antti Karttunen, Jan 15 2023

Keywords

• nonn

Crossrefs

Union of A046337 and A046470.

Positions of odd terms in A069345.

Cf. A001222, A359770 (characteristic function), A359772 (complement).

Programs

PARI

isA359771(n) = A359770(n);