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 A222650 #7 Jul 23 2025 02:52:15 %S A222650 1,1,2,11,34,131,438,2150,7676,32491,116096,533186,1945184,8362152, %T A222650 30561808,135650378,501075616,2155759835,7986345032,34780282521, %U A222650 129686419290,555913562689,2079094345694,8947148045345,33609869742022 %N A222650 Number of nX1 0..3 arrays with no more than floor(nX1/2) elements equal to at least one king-move neighbor, with new values introduced in row major 0..3 order. %C A222650 Column 1 of A222654 %H A222650 R. H. Hardin, <a href="/A222650/b222650.txt">Table of n, a(n) for n = 1..210</a> %e A222650 All solutions for n=3 %e A222650 ..0....0 %e A222650 ..1....1 %e A222650 ..2....0 %K A222650 nonn %O A222650 1,3 %A A222650 _R. H. Hardin_ Feb 27 2013