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 A229540 #9 Apr 27 2021 21:14:58 %S A229540 0,4212,59626,1379512,26566266,544403948,10551803060,205336122417, %T A229540 3913347537410,74172957575993,1391260426025666,25942784963976735, %U A229540 480614597100202422,8860662840757232528,162602761260788194310 %N A229540 Number of defective 3-colorings of a 7 X n 0..2 array connected horizontally, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order. %C A229540 Row 7 of A229534. %H A229540 R. H. Hardin, <a href="/A229540/b229540.txt">Table of n, a(n) for n = 1..210</a> %H A229540 R. H. Hardin, <a href="/A229540/a229540.txt">Empirical recurrence of order 92</a> %F A229540 Empirical recurrence of order 92 (see link above). %e A229540 Some solutions for n=3: %e A229540 0 1 2 0 1 0 0 1 0 0 1 0 0 1 0 0 1 2 0 1 0 %e A229540 0 1 2 0 1 0 0 2 0 0 1 0 0 2 2 0 1 0 1 2 0 %e A229540 0 2 0 0 2 0 0 2 0 0 1 0 0 1 0 2 1 0 0 2 1 %e A229540 1 2 0 0 1 0 0 2 0 2 1 2 0 2 0 0 2 0 0 2 0 %e A229540 1 2 1 0 2 0 0 1 0 2 1 2 0 2 0 0 2 1 1 2 1 %e A229540 1 2 1 1 2 1 2 2 0 0 0 2 1 2 1 1 2 1 1 2 1 %e A229540 1 2 1 0 0 1 0 1 0 2 1 2 1 2 1 1 2 0 0 2 1 %Y A229540 Cf. A229534. %K A229540 nonn %O A229540 1,2 %A A229540 _R. H. Hardin_, Sep 25 2013