The game of Mousetrap with n cards (given n letters and n envelopes, how many ways are there to fill the envelopes so that at least one letter goes into its right envelope?).
0, 1, 1, 4, 15, 76, 455, 3186, 25487, 229384, 2293839, 25232230, 302786759
1 seqfan posts
Wed Apr 18 15:15:28 CEST 2012 [seqfan] Mousetrap