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 A336303 #8 Feb 16 2025 08:34:00
%S A336303 1,1,0,0,6,0,180,630,1120,36288,441000,6579870,59734620,1252872192,
%T A336303 13668490836,162131872695,2971275208720,52783774330940,
%U A336303 1334562954639156,16933262255752698,406499325562503480,8838644883526856832,190698441426122689290
%N A336303 Number of ordered ways of writing the n-th n-gonal pyramidal number as a sum of n nonzero n-gonal pyramidal numbers.
%H A336303 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PyramidalNumber.html">Pyramidal Number</a>
%H A336303 <a href="/index/Ps#pyramidal_numbers">Index to sequences related to pyramidal numbers</a>
%F A336303 a(n) = [x^p(n,n)] (Sum_{k=1..n} x^p(n,k))^n, where p(n,k) = k * (k + 1) * (k * (n - 2) - n + 5) / 6 is the k-th n-gonal pyramidal number.
%e A336303 a(4) = 6 because the fourth square pyramidal number is 30 and we have [14, 14, 1, 1], [14, 1, 14, 1], [14, 1, 1, 14], [1, 14, 14, 1], [1, 14, 1, 14] and [1, 1, 14, 14].
%t A336303 Join[{1},Table[SeriesCoefficient[Sum[x^(k (k + 1) (k (n - 2) - n + 5)/6), {k, 1, n}]^n, {x, 0, n (n + 1) (n^2 - 3 n + 5)/6}], {n, 1, 22}]]
%Y A336303 Cf. A006484, A298858, A335634, A336091, A337797, A337798, A337799.
%K A336303 nonn
%O A336303 0,5
%A A336303 _Ilya Gutkovskiy_, Oct 04 2020