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 A359054 #16 Aug 27 2023 17:03:11 %S A359054 1,26,21953,5554571867,298500366308609377, %T A359054 11413459460309090640625021978, %U A359054 256925761343390078522337875137209684721665,6476754651706496208416137876625690606552226172163824554588 %N A359054 a(n) = Sum_{d|n} sigma_d(d)^d. %H A359054 Seiichi Manyama, <a href="/A359054/b359054.txt">Table of n, a(n) for n = 1..26</a> %F A359054 G.f.: Sum_{k >= 1} (sigma_k(k) * x)^k/(1 - x^k). %t A359054 a[n_] := DivisorSum[n, DivisorSigma[#, #]^# &]; Array[a, 8] (* _Amiram Eldar_, Aug 27 2023 *) %o A359054 (PARI) a(n) = sumdiv(n, d, sigma(d, d)^d); %o A359054 (PARI) my(N=10, x='x+O('x^N)); Vec(sum(k=1, N, (sigma(k, k)*x)^k/(1-x^k))) %Y A359054 Cf. A344047, A359052, A359053. %K A359054 nonn %O A359054 1,2 %A A359054 _Seiichi Manyama_, Dec 14 2022