%I A050974
%S A050974 2,16,265,16561,3157010,1828904402,3323590649777,18691199385898465,
%T A050974 325778072452564800064,17617718915229579206450786,
%U A050974 2954164381835835259001326344913,1536134628973698280539373190731911729
%N A050974 Number of binary arrangements on n X n array without three adjacent 1's 
               in a row or column.
%D A050974 S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.
%H A050974 S. R. Finch, <a href="http://algo.inria.fr/bsolve/constant/square/square.html">
               Hard Square Entropy Constant</a>
%H A050974 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               01-Matrix.html">Link to a section of The World of Mathematics.</a>
%Y A050974 Any connected three 1's gives A067968.
%Y A050974 Cf. A006506.
%Y A050974 Sequence in context: A140307 A114039 A090305 this_sequence A012188 A009764 
               A000182
%Y A050974 Adjacent sequences: A050971 A050972 A050973 this_sequence A050975 A050976 
               A050977
%K A050974 nonn
%O A050974 1,1
%A A050974 Eric Weisstein (eric(AT)weisstein.com)
%E A050974 More terms from Ron Hardin (rhhardin(AT)att.net), Feb 02 2002