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 A221295 #5 Jul 23 2025 01:49:51 %S A221295 1,1081,119972,22931365,4129628435,618825190371 %N A221295 Equals two maps: number of 7Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 7Xn array. %C A221295 Row 7 of A221290 %e A221295 Some solutions for n=3 %e A221295 ..0..1..0....0..0..1....0..0..0....0..0..0....0..0..0....0..1..0....0..0..0 %e A221295 ..1..0..0....0..0..1....0..1..1....1..1..1....0..1..1....1..0..1....0..0..1 %e A221295 ..0..0..1....1..0..0....0..1..1....0..1..1....1..0..0....1..0..0....1..0..1 %e A221295 ..0..0..0....0..0..0....0..0..0....0..1..1....0..0..0....0..0..0....1..0..1 %e A221295 ..0..0..1....1..1..0....0..0..1....0..0..1....1..1..1....0..1..1....1..0..1 %e A221295 ..1..0..0....1..1..0....1..0..0....1..0..0....0..1..1....0..1..1....0..1..0 %e A221295 ..0..1..0....0..0..0....0..1..0....1..0..0....0..1..0....0..1..0....0..0..0 %K A221295 nonn %O A221295 1,2 %A A221295 _R. H. Hardin_ Jan 09 2013