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 A146090 #4 Dec 18 2015 18:17:13 %S A146090 1,93,538,1532,3630,7540,14138,24480,39802,61520,91230,130708,181910, %T A146090 246972,328210,428120,549378,694840,867542,1070700,1307710,1582148, %U A146090 1897770,2258512,2668490,3132000,3653518,4237700,4889382,5613580 %N A146090 Number of n X n arrays of squares of integers with every (n-1)X(n-1) subblock summing to 4 and every element equal to at least one neighbor. %K A146090 nonn %O A146090 3,2 %A A146090 _R. H. Hardin_ Apr 14 2009