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 A308675 #18 May 11 2021 01:54:14
%S A308675 1,257,7625597484988,340282366920938463463374607431768276993,
%T A308675 2350988701644575015937473074444491355637331113544175043017503412556834518909454345703126
%N A308675 a(n) = Sum_{d|n} d^(d^2 * n).
%C A308675 The next term has 169 digits. - _Harvey P. Dale_, Feb 29 2020
%F A308675 L.g.f.: -log(Product_{k>=1} (1 - (k^(k^2)*x)^k)^(1/k)) = Sum_{k>=1} a(k)*x^k/k.
%t A308675 Table[Total[#^(#^2 n)&/@Divisors[n]],{n,5}] (* _Harvey P. Dale_, Feb 29 2020 *)
%t A308675 a[n_] := DivisorSum[n, #^(n * #^2) &]; Array[a, 5] (* _Amiram Eldar_, May 11 2021 *)
%o A308675 (PARI) {a(n) = sumdiv(n, d, d^(d^2*n))}
%o A308675 (PARI) N=10; x='x+O('x^N); Vec(x*deriv(-log(prod(k=1, N, (1-(k^k^2*x)^k)^(1/k)))))
%Y A308675 Column k=3 of A308676.
%Y A308675 Cf. A023887, A055225, A308670.
%K A308675 nonn
%O A308675 1,2
%A A308675 _Seiichi Manyama_, Jun 16 2019