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 A357504 #24 Jun 04 2023 08:56:02
%S A357504 1,3,4,6,7,9,10,11,13,15,16,18,21,22,24,25,27,28,29,31,34,36,37,38,39,
%T A357504 42,43,45,46,48,49,51,55,56,57,58,60,61,64,65,66,67,69,70,72,73,76,78,
%U A357504 79,81,83,84,87,88,91,92,93,94,97,99,100,101,102,105,106,108
%N A357504 Numbers that are the sum of two distinct triangular numbers.
%C A357504 This sequence differs from A020756 in excluding the terms that are twice a triangular number and that cannot be expressed as a sum of two distinct triangular numbers: 0, 2, 12, 20, 30, 90, 110, 132, ... = 2*A357529.
%F A357504 a(n) = (A339952(n) - 1)/4.
%t A357504 TriangularQ[n_]:=IntegerQ[(Sqrt[1+8n]-1)/2]; A000217[n_]:=n(n+1)/2; a={}; kn=0; For[k=0, k<=110, k++, For[h=0, A000217[h]<k/2, h++, If[TriangularQ[k - A000217[h]] && k>kn, AppendTo[a, k]; kn=k]]]; a (* _Stefano Spezia_, Nov 06 2022 *)
%Y A357504 Cf. A000217 (subsequence, excluding 0), A020756 (supersequence), A339952, A357505 (complement).
%Y A357504 Cf. A357529.
%K A357504 nonn,easy
%O A357504 1,2
%A A357504 _Stefano Spezia_, Oct 01 2022