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 A334035 #10 Feb 16 2025 08:34:00
%S A334035 1,45,225,585,2415,4725,9945,10395,31185,28665,45045,58905,143325,
%T A334035 257985,135135,225225,329175,487305,405405,831285,1091475,675675,
%U A334035 1396395,1576575,2927925,3132675,2436525,2027025,2567565,2297295,6235515,5360355,4729725,3828825,10503675
%N A334035 a(n) is the least integer that can be expressed as the difference of two hexagonal numbers in exactly n ways.
%C A334035 The least integer that can be expressed as the sum of one or more consecutive numbers congruent to 1 mod 4 in exactly n ways.
%C A334035 Index of first occurrence of n in A333816.
%H A334035 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexagonalNumber.html">Hexagonal Number</a>
%H A334035 <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%t A334035 nmax = 10000; A333816 = Rest[CoefficientList[Series[Sum[x^(k*(2*k - 1))/(1 - x^(4*k)), {k, 1, 1 + Sqrt[nmax/2]}], {x, 0, nmax}], x]]; Flatten[Table[FirstPosition[A333816, k], {k, 1, Max[A333816]}]] (* _Vaclav Kotesovec_, Apr 19 2020 *)
%Y A334035 Cf. A000384, A016813, A038547, A068314, A333816, A334010, A334034, A334036, A334037.
%K A334035 nonn
%O A334035 1,2
%A A334035 _Ilya Gutkovskiy_, Apr 12 2020
%E A334035 More terms from _Jinyuan Wang_, Apr 13 2020