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 A225254 #14 Oct 14 2023 00:04:28
%S A225254 1,4,12,25,43,67,95,130,169,215,267,324,385,454,527,606,692,784,880,
%T A225254 983,1090,1205,1325,1449,1578,1716,1860,2008,2162,2323,2488,2661,2838,
%U A225254 3022,3210,3403,3605,3813,4025,4242,4464,4695,4930,5173,5420,5673,5933,6197
%N A225254 Number of distinct values of the sum of 3 products of two 0..n integers.
%H A225254 R. H. Hardin, <a href="/A225254/b225254.txt">Table of n, a(n) for n = 0..999</a>
%o A225254 (Python)
%o A225254 from itertools import combinations_with_replacement
%o A225254 def A225254(n): return len({sum(x) for x in combinations_with_replacement({i*j for i in range(n+1) for j in range(i+1)},3)}) # _Chai Wah Wu_, Oct 13 2023
%Y A225254 Row 3 of A225252.
%K A225254 nonn
%O A225254 0,2
%A A225254 _R. H. Hardin_, May 04 2013
%E A225254 a(0)=1 prepended by _Alois P. Heinz_, Oct 13 2023