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 A319185 #68 Feb 16 2025 08:33:56
%S A319185 0,1,6,7,15,21,22,28,43,45,49,50,66,73,88,91,94,95,111,120,139,153,
%T A319185 154,157,160,161,190,202,211,230,231,245,251,252,273,276,277,322,325,
%U A319185 343,350,364,365,371,372,378,421,430,435,463,475,496,503,507,518,524,525,554,561
%N A319185 Numbers that are sums of consecutive hexagonal numbers (A000384).
%H A319185 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexagonalNumber.html">Hexagonal Number</a>
%t A319185 anmax = 1000; nmax = Floor[Sqrt[anmax/2]] + 1; Select[Union[Flatten[Table[Sum[k*(2*k-1), {k, i, j}], {i, 0, nmax}, {j, i, nmax}]]], # <= anmax &] (* _Vaclav Kotesovec_, Dec 21 2018 *)
%Y A319185 Cf. A000384, A002412, A034705, A034706, A319184, A322636, A322637.
%K A319185 nonn
%O A319185 1,3
%A A319185 _Ilya Gutkovskiy_, Dec 21 2018