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 A359660 #11 Jan 10 2023 06:44:44
%S A359660 0,1,3,12,64,441,3855,41464,533736,8071785,141351715,2829417276,
%T A359660 64038928728,1624347614737,45822087138879,1427872211276376,
%U A359660 48858282302548240,1826209988254883889,74216973833968292451,3265676709281560408780
%N A359660 a(n) = Sum_{k=0..n} k^(2 * (n-k) + 1).
%F A359660 G.f.: Sum_{k>=0} k * x^k/(1 - k^2 * x).
%o A359660 (PARI) a(n, s=1, t=2) = sum(k=0, n, k^(t*(n-k)+s));
%o A359660 (PARI) my(N=20, x='x+O('x^N)); concat(0, Vec(sum(k=0, N, k*x^k/(1-k^2*x))))
%Y A359660 Cf. A234568, A349882.
%Y A359660 Cf. A000217, A003101.
%K A359660 nonn,easy
%O A359660 0,3
%A A359660 _Seiichi Manyama_, Jan 10 2023