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

Author

N. J. A. Sloane, Mar 15 2014

Keywords

• nonn
• more

Links

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

Crossrefs

Cf. A000315, A002860, A000010, A141599.

Formula

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