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 A308692 #27 May 09 2021 02:50:57
%S A308692 1,2,2,6,2,27,2,82,83,283,2,2047,2,4147,7188,20546,2,125964,2,343407,
%T A308692 533844,1048699,2,10076747,390627,16777387,43053284,84003927,2,
%U A308692 667311413,2,1342439682,3486799044,4294967587,249905428,52916914768,2,68719477099,282429565044
%N A308692 a(n) = Sum_{d|n} d^(2*(n/d - 1)).
%H A308692 Robert Israel, <a href="/A308692/b308692.txt">Table of n, a(n) for n = 1..3143</a>
%F A308692 L.g.f.: -log(Product_{k>=1} (1 - k^2*x^k)^(1/k^3)) = Sum_{k>=1} a(k)*x^k/k.
%F A308692 a(p) = 2 for prime p.
%F A308692 G.f.: Sum_{k>=1} x^k/(1 - k^2*x^k). - _Ilya Gutkovskiy_, Jul 25 2019
%p A308692 N:=100: # for a(1)..a(N)
%p A308692 g:= add(x^k/(1-k^2*x^k),k=1..N):
%p A308692 S:= series(g,x,N+1):
%p A308692 seq(coeff(S,x,j),j=1..N); # _Robert Israel_, Apr 05 2020
%t A308692 a[n_] := DivisorSum[n, #^(2*(n/# - 1)) &]; Array[a, 39] (* _Amiram Eldar_, May 09 2021 *)
%o A308692 (PARI) {a(n) = sumdiv(n, d, d^(2*(n/d-1)))}
%o A308692 (PARI) N=66; x='x+O('x^N); Vec(x*deriv(-log(prod(k=1, N, (1-k^2*x^k)^(1/k^3)))))
%Y A308692 Column k=2 of A308694.
%K A308692 nonn,look
%O A308692 1,2
%A A308692 _Seiichi Manyama_, Jun 17 2019