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 A243511 #7 Aug 29 2015 03:50:48 %S A243511 1,1,6,110,18343,9382388,43019044258,558605693874364, %T A243511 66236678406528448449,21324218858696872235790649, %U A243511 63694548993039561351614359349824,503614181552476916158019971522161589536,37393123107750749849065997795023579513072683993,7226766277015485498828489748946241590630740791829515424 %N A243511 Number of ways half the maximal number of domicules can be placed on an n X n square. %F A243511 a(n) = A243424(n,floor(n^2/4)). %e A243511 a(2) = 6: %e A243511 +---+ +---+ +---+ +---+ +---+ +---+ %e A243511 |o-o| | | |o | | o| |o | | o| %e A243511 | | | | || | | || | \ | | / | %e A243511 | | |o-o| |o | | o| | o| |o | %e A243511 +---+ +---+ +---+ +---+ +---+ +---+. %Y A243511 Cf. A243510. %K A243511 nonn %O A243511 0,3 %A A243511 _Alois P. Heinz_, Jun 05 2014