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 A207105 #8 Jul 22 2025 20:01:36 %S A207105 2,16,98,643,4047,22714,139341,794118,4654884,27655332,162017453, %T A207105 985389943,5963777274,36963453329,232521285314,1479703961900, %U A207105 9627524117464 %N A207105 Number of n X n 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically. %C A207105 Diagonal of A207111 %e A207105 Some solutions for n=4 %e A207105 ..1..1..1..1....0..0..1..0....1..0..0..1....1..1..0..1....1..1..1..0 %e A207105 ..1..1..0..0....1..0..1..0....0..1..0..0....0..0..1..0....0..1..0..0 %e A207105 ..1..1..1..1....0..0..1..0....1..1..0..1....0..1..0..1....0..1..0..0 %e A207105 ..1..1..0..0....0..0..1..0....0..1..0..0....0..0..1..0....0..1..0..0 %K A207105 nonn %O A207105 1,1 %A A207105 _R. H. Hardin_ Feb 15 2012