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 A229678 #10 Apr 28 2021 01:25:42 %S A229678 0,2,888,186576,58038768,33555543408,39647663129952, %T A229678 100358466494032656,559874175467657854896,7007180500895781669589584 %N A229678 Number of defective 3-colorings of an n X n 0..2 array connected diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order. %C A229678 Diagonal of A229685. %e A229678 Some solutions for n=3: %e A229678 0 0 0 0 1 1 0 1 0 0 1 0 0 1 1 0 0 1 0 0 1 %e A229678 1 0 1 0 2 2 2 2 1 2 2 1 0 0 1 1 1 1 2 0 1 %e A229678 1 2 2 2 1 2 2 0 1 0 1 1 2 2 2 1 2 2 2 2 1 %K A229678 nonn,more %O A229678 1,2 %A A229678 _R. H. Hardin_, Sep 27 2013