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 A195800 #6 Jul 22 2025 12:46:35 %S A195800 1,1,4,64,496,24928,17528896,3850960912 %N A195800 Number of triangular nXnXn 0..3 arrays with all rows and diagonals having the same length having the same sum, with corners zero. %C A195800 Column 3 of A195805 %e A195800 Some solutions for n=5 %e A195800 ......0..........0..........0..........0..........0..........0..........0 %e A195800 .....3.3........1.0........2.0........2.2........1.0........0.1........2.0 %e A195800 ....0.3.0......1.1.3......3.0.3......1.0.1......1.1.1......0.2.0......3.0.3 %e A195800 ...3.3.3.3....1.2.0.0....0.0.0.2....2.0.0.2....0.1.1.1....1.2.2.0....0.0.0.2 %e A195800 ..0.3.0.3.0..0.0.2.1.0..0.2.3.0.0..0.2.1.2.0..0.1.1.0.0..0.0.0.1.0..0.2.3.0.0 %K A195800 nonn %O A195800 1,3 %A A195800 _R. H. Hardin_ Sep 23 2011