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 A275869 #19 May 31 2017 03:26:47 %S A275869 2,2,11,51,922,25618,1597350,169413040,33716225195,11838480390673, %T A275869 7588965091313449,8705702554970941096,18079208010076976255573, %U A275869 67519585404524909086260614,455193583190737164106702088892,5527752160260327852724215089473548 %N A275869 Number of nonequivalent ways to place k>=0 nonattacking kings on an n X n board. %C A275869 Also number of nonequivalent ways to tile an n+1 X n+1 square with 1 X 1 and 2 X 2 tiles. %C A275869 Also row sum of triangle A236679. %C A275869 Rotations and reflections of a placement are not counted. If they are to be counted, see A063443. %H A275869 Andrew Howroyd, <a href="/A275869/b275869.txt">Table of n, a(n) for n = 1..30</a> %Y A275869 Cf. A236679, A063443. %K A275869 nonn %O A275869 1,1 %A A275869 _Heinrich Ludwig_, Dec 11 2016 %E A275869 a(10)-a(16) from _Andrew Howroyd_, May 30 2017