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 A216087 #9 Jul 22 2025 23:30:11 %S A216087 2,27,203,15144,373780,87852160,4044766240,2004646634218, %T A216087 142953007126612,123560104158582188,12361734369562410736 %N A216087 Number of horizontal and antidiagonal neighbor colorings of the odd squares of a 5Xn array with new integer colors introduced in row major order. %C A216087 Row 5 of A216084 %e A216087 Some solutions for n=4 %e A216087 ..x..0..x..1....x..0..x..1....x..0..x..1....x..0..x..1....x..0..x..1 %e A216087 ..2..x..3..x....2..x..3..x....2..x..3..x....2..x..3..x....2..x..3..x %e A216087 ..x..1..x..2....x..2..x..3....x..0..x..4....x..4..x..0....x..4..x..5 %e A216087 ..3..x..0..x....0..x..4..x....1..x..3..x....1..x..5..x....0..x..4..x %e A216087 ..x..1..x..3....x..2..x..1....x..5..x..4....x..1..x..2....x..6..x..3 %K A216087 nonn %O A216087 1,1 %A A216087 _R. H. Hardin_ Sep 01 2012