A359821 Numbers k whose arithmetic derivative, A003415(k), has the opposite parity to k.

1, 2, 6, 9, 10, 14, 15, 18, 21, 22, 25, 26, 30, 33, 34, 35, 38, 39, 42, 46, 49, 50, 51, 54, 55, 57, 58, 62, 65, 66, 69, 70, 74, 77, 78, 81, 82, 85, 86, 87, 90, 91, 93, 94, 95, 98, 102, 106, 110, 111, 114, 115, 118, 119, 121, 122, 123, 126, 129, 130, 133, 134, 135, 138, 141, 142, 143, 145, 146, 150, 154

Offset: 1

Author

Antti Karttunen, Jan 14 2023

Keywords

• nonn
• easy

Crossrefs

Cf. A003415, A359820 (characteristic function), A359822 (complement).

Positions of odd terms in A129283 and in A168036.

Programs

PARI

isA359821(n) = A359820(n);

Extensions

Name edited by Peter Munn, Jan 14 2023