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 A327792 #15 Oct 30 2019 13:24:24 %S A327792 0,18,168,78,243,130,553,455,515,658,865,945,633,1918,2258,1385,1583, %T A327792 2828,2135,2335,2785,4533,3168,3478,2790,3868,4193,7328,4953,5278, %U A327792 6390,8148,8015,4585,9160,10485,7613,12333,12025,10178,9923,9720,12558,11340,17420,11753,14893,16155,16415,14343,18053,19803,16608,27283 %N A327792 a(n) is the greatest nonnegative number which has a partition into a triangular number (A000217), a square number (A000290), and a pentagonal number (A000326) in n different ways. %C A327792 The largest nonnegative number k such that A240088(k) = n. %H A327792 Robert G. Wilson v, <a href="/A327792/b327792.txt">Table of n, a(n) for n = 1..200</a> %e A327792 a(0) does not exist since all numbers can be represented as the sum of a triangular, square & pentagonal number. %t A327792 f[n_] := Block[{j, k = 1, lenq, lenr, v = {}, t = PolygonalNumber[3, Range[0, 1 + Sqrt[2 n]]], s = PolygonalNumber[4, Range[0, 1 + Sqrt[n]]], p = PolygonalNumber[5, Range[0, 2 + Sqrt[2 n/3]]]}, u = Select[Union[Join[t, s, p]], # < n + 1 &]; q = IntegerPartitions[n, {3}, u]; lenq = 1 + Length@q; While[k < lenq, j = 1; r = q[[k]]; rr = Permutations@r; lenr = 1 + Length@rr; While[j < lenr, If[ MemberQ[t, rr[[j, 1]]] && MemberQ[s, rr[[j, 2]]] && MemberQ[p, rr[[j, 3]]], AppendTo[v, rr[[j]]]]; j++]; k++]; Length@v]; %Y A327792 Cf. A000217, A000290, A000326, A240088, A275999, A327793. %K A327792 nonn %O A327792 1,2 %A A327792 _Robert G. Wilson v_, Sep 25 2019