login
Number of n X n binary arrays, symmetric about both diagonal and antidiagonal, with every 1 adjacent to at least one other 1, but at most one 1 adjacent horizontally and at most one 1 adjacent vertically.
0

%I #3 Mar 31 2012 12:35:07

%S 1,2,3,11,31,171,719,5907,40576,574191,6118805,134458817,2328856652,

%T 81657178991,2239533631682,126154274091928,5530047112752039,

%U 494646201440552586,34629959352847199652,4953721399562434015229

%N Number of n X n binary arrays, symmetric about both diagonal and antidiagonal, with every 1 adjacent to at least one other 1, but at most one 1 adjacent horizontally and at most one 1 adjacent vertically.

%K nonn

%O 1,2

%A _R. H. Hardin_, Sep 08 2008