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 A265966 #6 Apr 20 2020 19:39:19 %S A265966 5,288,6112,74248,631264,5006296,34825856,249438952,1579115104 %N A265966 Number of n X n 0..4 arrays with the absolute differences of each element with its with horizontal and vertical neighbors unique. %C A265966 Diagonal of A265973. %e A265966 Some solutions for n=4 %e A265966 ..3..0..4..4....3..1..0..4....4..1..3..3....3..4..0..3....4..2..2..3 %e A265966 ..3..1..1..3....4..1..3..4....4..1..0..4....1..1..0..3....3..1..4..3 %e A265966 ..4..4..0..0....4..0..3..1....3..3..0..1....0..3..4..4....0..1..4..0 %e A265966 ..0..3..3..2....3..0..4..1....0..2..2..3....2..3..1..0....4..3..3..0 %Y A265966 Cf. A265973. %K A265966 nonn %O A265966 1,1 %A A265966 _R. H. Hardin_, Dec 19 2015