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 A374894 #5 Sep 15 2024 10:55:51
%S A374894 0,-1,0,-27,-256,1875,0,252105,4718592,-55801305,0,-18415376595,
%T A374894 -515978035200,8479520844795,0,5195043369140625,193953851139686400,
%U A374894 -4086470036057634225,0,-4014187339733760264075,-187280916480000000000000,4816074142389727429287075,0
%N A374894 Obverse convolution (n)**(n*(-1)^n); see Comments.
%C A374894 See A374848 for the definition of obverse convolution and a guide to related sequences.
%t A374894 s[n_] := n; t[n_] := (-1)^n n;
%t A374894 u[n_] := Product[s[k] + t[n - k], {k, 0, n}]
%t A374894 Table[u[n], {n, 0, 26}]
%Y A374894 Cf. A000027, A038608, A374848.
%K A374894 sign
%O A374894 0,4
%A A374894 _Clark Kimberling_, Sep 14 2024