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 A379498 #7 Jan 05 2025 22:35:28
%S A379498 2,4,7,12,3,5,13,20,36,75,23,-175,73,105,195,300,123,-500,373,-375,
%T A379498 1035,2175,623,1215,1870,3525,5575,5625,5,-161,19,28,-87,-249,-15,
%U A379498 -8680,103,-915,-135,-1995,173,-4025,523,735,1533,1275,873,-9275,2610,4900,7125,14175,4373,8505,12675,25809,37125,78729,47
%N A379498 a(n) = A276086(1+n) - A276086(A001065(n)), where A276086 is the primorial base exp-function, and A001065 is the sum of proper divisors of n.
%H A379498 Antti Karttunen, <a href="/A379498/b379498.txt">Table of n, a(n) for n = 1..30030</a>
%H A379498 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>.
%H A379498 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F A379498 a(n) = A276086(1+n) - A379493(n).
%F A379498 For even n, a(n) = A379494(n).
%o A379498 (PARI)
%o A379498 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A379498 A379498(n) = (A276086(1+n) - A276086(sigma(n)-n));
%Y A379498 Cf. A001065, A276086, A379493, A379494.
%Y A379498 Cf. also A379496.
%K A379498 sign
%O A379498 1,1
%A A379498 _Antti Karttunen_, Jan 05 2025