A086502 Number of ordered pairs (a,b) of elements of the symmetric group S_n such that the pair a,b generates a proper subgroup of S_n.

0, 1, 18, 360, 7560, 289440, 9828000, 631169280, 46449002880, 4526271187200, 524461965350400, 74044329341875200, 12211524764030592000

Offset: 1

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Sep 09 2003

Keywords

• nonn

Crossrefs

Cf. A071605.

Formula

a(n) = n!^2 - A071605(n).

Extensions

a(10)-(13) from Stephen A. Silver, Feb 21 2013