A071308 a(n) = (1/2) * (number of n X n 0..9 matrices with MM' mod 10 = I).

1, 8, 720, 691200, 6739200000, 668528640000000, 663347543040000000000, 6622861869711360000000000000, 660754650163765248000000000000000000, 660543208675712843120640000000000000000000000, 6601093143555139842468151296000000000000000000000000000

Offset: 1

Author

R. H. Hardin, Jun 11 2002

Keywords

• nonn

Crossrefs

Cf. A003053, A071302, A071303, A071304, A071305, A071306, A071307, A071309, A071310.

Formula

a(n) = A003053(n) * A071304(n). - Max Alekseyev, Nov 06 2022

Extensions

Terms a(6) onward from Max Alekseyev, Nov 06 2022