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 A223498 #7 Mar 17 2023 01:14:43 %S A223498 1,19,1519,426359,515473927,2519813048575,51596648899152901, %T A223498 4382197669772597921079,1555039484181265199709474223, %U A223498 2303272223887812126256525632339813 %N A223498 Petersen graph (3,1) coloring a rectangular array: number of n X n 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,3 3,5 3,4 1,2 1,4 4,5 2,0 2,5 and every array movement to a horizontal, diagonal or antidiagonal neighbor moves along an edge of this graph, with the array starting at 0. %C A223498 Diagonal of A223504. %e A223498 Some solutions for n=3 %e A223498 ..0..3..0....0..2..5....0..3..0....0..2..1....0..1..0....0..1..0....0..2..0 %e A223498 ..0..2..0....0..3..0....4..1..4....0..2..1....4..1..4....2..1..0....5..3..0 %e A223498 ..0..2..5....0..3..0....2..5..2....0..2..5....4..3..4....0..1..0....0..3..5 %Y A223498 Cf. A223504. %K A223498 nonn %O A223498 1,2 %A A223498 _R. H. Hardin_, Mar 21 2013