A187454 - OEIS

%I #4 Mar 31 2012 12:36:08

%S 81,5175,1293651,983320335,2806943351103,25357269654789183,

%T 816485466267634598145

%N Number of (n+1)X(n+1) 0..2 arrays with the array of 2X2 subblock determinants symmetric

%C Column 2 of A187457

%e Some solutions for 4X4

%e ..0..0..2..0....0..0..2..0....0..0..0..1....0..0..2..1....0..0..2..0

%e ..2..1..1..2....0..0..2..1....1..1..0..0....1..0..0..0....1..0..1..2

%e ..2..0..1..0....2..2..0..0....0..0..0..1....1..0..1..0....2..0..0..0

%e ..2..2..0..0....0..1..0..0....2..0..1..1....1..0..1..2....0..2..0..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 10 2011