A324549 a(n) = A324543(2*A000040(n)).

3, 2, 5, 2, 16, 20, 48, 2, 288, 278, 688, 260, 2736, 4136, 19024, 2, 43696, 88976, 174768, 61700, 1003088, 853928, 2796208, 264200, 15458560, 15515024, 76835312, 15790340, 191089888, 420297968, 715827888, 6701060, 4021980256, 3609034832, 16962926080, 4514867216, 45916115936, 57141553616, 244626722384, 4278255620

Offset: 1

Author

Antti Karttunen, Mar 07 2019

Keywords

• nonn

Comments

Term 2 occurs (at least) at n = 2, 4, 8 and 16. See A019434.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..331

Crossrefs

Cf. A000040, A000051, A000079, A000203, A019434, A324543.

Programs

PARI

A324549(n) = A324543(2*prime(n));

Formula

a(n) = A324543(2*A000040(n)).

a(n) = sigma(2^n + 1) - 2^n, for n>1. - Ridouane Oudra, Jul 15 2023