Number of nX2 array permutations with each element moving one space diagonally, horizontally or vertically
1, 4, 13, 45, 160, 565, 2005, 7108, 25209, 89401, 317056, 1124425, 3987721
2 seqfan posts
Thu Apr 21 11:56:48 CEST 2011 [seqfan] Re: Symmetric Linear Recorrence Coefficients?