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 A145773 #9 Jul 10 2025 14:30:37 %S A145773 1,5,25,314,7358,349511,32855368,6141909014,2284689480141, %T A145773 1689669248970784,2485350221377308028,7269523179423750332937, %U A145773 42286820404292801713317670,489171492515135237008883532896 %N A145773 Number of n X n binary arrays with all ones connected only either two adjacent vertically or two adjacent horizontally. %e A145773 Maximal 5 X 5 example %e A145773 .1.1.0.0.1 %e A145773 .0.0.0.0.1 %e A145773 .1.0.1.1.0 %e A145773 .1.0.0.0.1 %e A145773 .0.1.1.0.1 %K A145773 nonn,more %O A145773 1,2 %A A145773 _R. H. Hardin_, Oct 18 2008