This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A324549 #13 Jul 15 2023 15:01:08 %S A324549 3,2,5,2,16,20,48,2,288,278,688,260,2736,4136,19024,2,43696,88976, %T A324549 174768,61700,1003088,853928,2796208,264200,15458560,15515024, %U A324549 76835312,15790340,191089888,420297968,715827888,6701060,4021980256,3609034832,16962926080,4514867216,45916115936,57141553616,244626722384,4278255620 %N A324549 a(n) = A324543(2*A000040(n)). %C A324549 Term 2 occurs (at least) at n = 2, 4, 8 and 16. See A019434. %H A324549 Antti Karttunen, <a href="/A324549/b324549.txt">Table of n, a(n) for n = 1..331</a> %F A324549 a(n) = A324543(2*A000040(n)). %F A324549 a(n) = sigma(2^n + 1) - 2^n, for n>1. - _Ridouane Oudra_, Jul 15 2023 %o A324549 (PARI) A324549(n) = A324543(2*prime(n)); %Y A324549 Cf. A000040, A000051, A000079, A000203, A019434, A324543. %K A324549 nonn %O A324549 1,1 %A A324549 _Antti Karttunen_, Mar 07 2019