A181236 - OEIS

%I #3 Mar 31 2012 12:35:49

%S 2,2,4,2,8,14,2,22,182,140,2,72,3362,49772,4322,2,254,69302,33235358,

%T 113400002,434542,2,926,1513514,27896484332,5210265060002,

%U 4027811102702,144109562,2,3434,34306274,26012734507190,298289608088472002

%N T(n,k)=Number of (k*n)Xn binary matrices with all row sums equal and all column sums equal

%C Table starts

%C ............2...................2....................2..................2

%C ............4...................8...................22.................72

%C ...........14.................182.................3362..............69302

%C ..........140...............49772.............33235358........27896484332

%C .........4322...........113400002........5210265060002.298289608088472002

%C .......434542.......4027811102702.90698868503010138802...................

%C ....144109562.1237505791330809002........................................

%C .165431317452............................................................

%H R. H. Hardin, <a href="/A181236/b181236.txt">Table of n, a(n) for n=1..41</a>

%e All solutions for 6X2

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

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

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

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

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

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

%e ...

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

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

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

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

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

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

%e ...

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

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

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

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

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

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

%Y Column 1 is A067209

%Y Row 2 is twice A112849

%K nonn,tabl

%O 1,1

%A _R. H. Hardin_ Oct 10 2010