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 A216462 #6 Jul 22 2025 23:32:23 %S A216462 2,5,20,203,3429,83440,2711768,112073062,5691327040,346212384169, %T A216462 24737419691764,2043836452962923,192779435018929754, %U A216462 20538493062072286871,2449347793873500266618,324446721789278481458200 %N A216462 Number of horizontal, diagonal and antidiagonal neighbor colorings of the even squares of a 4Xn array with new integer colors introduced in row major order. %C A216462 Row 4 of A216460 %H A216462 R. H. Hardin, <a href="/A216462/b216462.txt">Table of n, a(n) for n = 1..20</a> %e A216462 Some solutions for n=4 %e A216462 ..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x %e A216462 ..x..2..x..0....x..2..x..3....x..2..x..3....x..2..x..3....x..2..x..3 %e A216462 ..3..x..4..x....0..x..4..x....1..x..4..x....3..x..0..x....4..x..0..x %e A216462 ..x..5..x..1....x..2..x..5....x..5..x..3....x..4..x..2....x..5..x..4 %K A216462 nonn %O A216462 1,1 %A A216462 _R. H. Hardin_ Sep 07 2012