A067210 - OEIS

%I #10 Jun 01 2017 03:01:35

%S 3,9,87,5673,2577513,8459809773,207495141083975,39125696231091082665,

%T 57899300601363050181107733,683382115404724657577266518831159,

%U 65156055488094891194179319045960728827635,50704966066306827486637758645370695372532720829085

%N Number of n X n 0..2 matrices with all row and column sums equal.

%e Some solutions for n=4

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

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

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

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

%Y Row 2 of A202784.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 20 2002

%E added one term and example - R. H. Hardin, Jan 05 2012

%E a(8)-a(12) from _Andrew Howroyd_, Jun 01 2017