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 A374878 #15 Sep 16 2024 09:22:05
%S A374878 4,49,1000,28561,1048576,47045881,2494357888,152587890625,
%T A374878 10578455953408,819628286980801,70188843638032384,6582952005840035281,
%U A374878 671088640000000000000,73885357344138503765449,8737103395697172336050176,1104427674243920646305299201
%N A374878 Obverse convolution (3n+2)**(3n+2); see Comments.
%C A374878 See A374848 for the definition of obverse convolution and a guide to related sequences.
%C A374878 If k>=0, then a(2k) is even and a(2k+1) is a square.
%F A374878 From _Vaclav Kotesovec_, Sep 13 2024: (Start)
%F A374878 a(n) = (3*n+4)^(n+1).
%F A374878 a(n) ~ exp(4/3) * 3^(n+1) * n^(n+1). (End)
%t A374878 s[n_] := 3 n + 2; t[n_] := 3 n + 2;
%t A374878 u[n_] := Product[s[k] + t[n - k], {k, 0, n}]
%t A374878 Table[u[n], {n, 0, 17}]
%t A374878 (* or *)
%t A374878 Table[(3*n+4)^(n+1), {n,0,20}] (* _Vaclav Kotesovec_, Sep 13 2024 *)
%Y A374878 Cf. A016789, A374848, A374877.
%K A374878 nonn,easy
%O A374878 0,1
%A A374878 _Clark Kimberling_, Sep 13 2024