Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.
A215871
Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =12a(6) =29a(7) =110a(8) =290a(9) =1274a(10) =3532a(11) =17136a(12) =49100a(13) =255816a(14) =750325a(15) =4124406a(16) =12310294a(17) =70549050a(18) =213446666a(19) =1264752060a(20) =3868253164a(21) =23555382240a(22) =72686739116a(23) =452806924752
External references
- oeis: A215871