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 A195797 #7 Jul 22 2025 12:46:20 %S A195797 1,1,4,125,5052,5828215,479534519840 %N A195797 Number of triangular nXnXn 0..n arrays with all rows and diagonals having the same length having the same sum, with corners zero. %C A195797 Diagonal of A195805 %e A195797 Some solutions for n=5 %e A195797 ......0..........0..........0..........0..........0..........0..........0 %e A195797 .....0.1........5.0........5.0........4.3........5.0........1.0........3.2 %e A195797 ....4.4.3......5.0.5......3.0.5......4.0.3......3.0.4......3.1.3......5.1.5 %e A195797 ...1.2.3.1....0.0.0.5....0.4.2.3....2.1.2.4....0.2.1.4....0.1.1.1....1.4.4.2 %e A195797 ..0.0.5.0.0..0.5.5.0.0..0.5.1.2.0..0.5.2.3.0..0.5.2.1.0..0.1.3.0.0..0.4.2.3.0 %K A195797 nonn %O A195797 1,3 %A A195797 _R. H. Hardin_ Sep 23 2011