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 A346523 #30 Nov 20 2021 20:19:17 %S A346523 1,1,1,1,2,2,3,3,5,5,7,9,11,11,18,17,22,23,29,31,38,37,46,49,58,59,72, %T A346523 76,86,90,106,115,131,140,159,177,189,204,236,254,274,292,328,355,398, %U A346523 404,455,485,518,555,622,647,698,727,808,837,922,939,1032,1100 %N A346523 Number of sum pyramids for n. %C A346523 A sum pyramid for n is defined to be a pyramid with n at its apex, all pairs of adjacent members (x, y) of rows 2,3,4,... sum to the element immediately above, every element is positive and distinct, rows are complete (length of row m = length of row (m-1) + 1), reflections are not counted, and the pyramid is maximal (i.e., not part of a larger pyramid that qualifies). An example of the meaning of "maximal" can be seen in the Example section: the pyramids %C A346523 . %C A346523 9 9 %C A346523 6 3 and 5 4 %C A346523 . %C A346523 are not counted because they consist of the top 2 rows of larger (3-row) pyramids that are counted. [Clarified by _Peter Munn_, Nov 20 2021] %H A346523 J. Stauduhar, <a href="/A346523/a346523.txt">Python program</a> %e A346523 The five pyramids for a(9) are: %e A346523 9 9 9 %e A346523 9 9 6 3 6 3 5 4 %e A346523 8 1 7 2 5 1 2 4 2 1 2 3 1 %o A346523 (Python) See Links section. %Y A346523 Cf. A028307 (record pyramid heights), A337766, A348850. %K A346523 nonn %O A346523 1,5 %A A346523 _J. Stauduhar_, Jul 21 2021 %E A346523 Definition aligned with A028307 by _Peter Munn_, Nov 20 2021