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 A145857 #3 Mar 31 2012 12:35:08 %S A145857 1,2,5,12,72,513,4531,68662,1429824,40840428,1747979822,106711196102, %T A145857 9237029528023,1158315077977449,208422835867809541, %U A145857 53674442198900292691,19878424340459715152560,10569643478952360023168707 %N A145857 Number of n X n binary arrays with all ones connected only in two by two blocks. %e A145857 Maximal 7 X 7 example %e A145857 .0.0.0.1.1.0.0 %e A145857 .1.1.0.1.1.0.0 %e A145857 .1.1.0.0.0.1.1 %e A145857 .0.0.1.1.0.1.1 %e A145857 .0.0.1.1.0.0.0 %e A145857 .1.1.0.0.0.1.1 %e A145857 .1.1.0.0.0.1.1 %K A145857 nonn %O A145857 1,2 %A A145857 _R. H. Hardin_, Oct 22 2008