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 A337764 #8 Feb 16 2025 08:34:00
%S A337764 1,1,2,7,124,14371,12842911,103590035354,8621925847489749,
%T A337764 8307493939404888703058,102488432265617100812550713499,
%U A337764 17706351554929677399562928448484650120,46435685450659378932235460132506329282776942795
%N A337764 Number of compositions (ordered partitions) of the n-th n-gonal number into n-gonal numbers.
%H A337764 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PolygonalNumber.html">Polygonal Number</a>
%H A337764 <a href="/index/Com#comp">Index entries for sequences related to compositions</a>
%H A337764 <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%F A337764 a(n) = [x^p(n,n)] 1 / (1 - Sum_{k=1..n} x^p(n,k)), where p(n,k) = k * (k * (n - 2) - n + 4) / 2 is the k-th n-gonal number.
%e A337764 a(3) = 7 because the third triangular number is 6 and we have [6], [3, 3], [3, 1, 1, 1], [1, 3, 1, 1], [1, 1, 3, 1], [1, 1, 1, 3] and [1, 1, 1, 1, 1, 1].
%Y A337764 Cf. A011782, A060354, A224366, A224677, A337762, A337763.
%K A337764 nonn
%O A337764 0,3
%A A337764 _Ilya Gutkovskiy_, Sep 19 2020