A332459 Odd part of 1+sigma(n).

1, 1, 5, 1, 7, 13, 9, 1, 7, 19, 13, 29, 15, 25, 25, 1, 19, 5, 21, 43, 33, 37, 25, 61, 1, 43, 41, 57, 31, 73, 33, 1, 49, 55, 49, 23, 39, 61, 57, 91, 43, 97, 45, 85, 79, 73, 49, 125, 29, 47, 73, 99, 55, 121, 73, 121, 81, 91, 61, 169, 63, 97, 105, 1, 85, 145, 69, 127, 97, 145, 73, 49, 75, 115, 125, 141, 97, 169, 81, 187, 61, 127

Offset: 1

Author

Antti Karttunen, Feb 16 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537
• Index entries for sequences related to binary expansion of n
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A000265, A002487, A088580, A161942, A202274, A324294, A332454, A332455.

Programs

PARI

A332459(n) = { my(s=1+sigma(n)); (s>>valuation(s,2)); };

Formula

a(n) = A000265(A088580(n)) = A000265(1+sigma(n)).

A002487(a(n)) = A324294(n).

a(2^n) = 0 for all n >= 0. [Zero occurs at least also at a(25). See A202274]