A238838 Number of 2n X 2n addition squares in which every digram (s,s;), s' != s, appears once horizontally and once vertically.

2, 48, 5760, 5806080, 75246796800, 1780537083494400, 115939740156316876800, 19864514173849162481664000

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Gilbert, E. N., Latin squares which contain no repeated digrams, SIAM Rev. 7 1965 189--198. MR0179095 (31 #3346).

Formula

a(n) = (2*n)!*A141599(n)^2/phi(n).

Crossrefs

Cf. A000315, A002860, A000010, A141599.

Sequence in context: A087085 A067626 A053071 * A002820 A196448 A053290

Adjacent sequences: A238835 A238836 A238837 * A238839 A238840 A238841

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 15 2014

Status

approved