302786759

Appears in sequences

• 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?).at n=12A002467
• Number T(n,k) of permutations p of [n] such that min_{j=1..n} |p(j)-j| = k; triangle T(n,k), n >= 0, 0 <= k <= floor(n/2), read by rows.at n=42A299789
• Number of permutations p of [2n] having at least one index i with |p(i)-i| = n.at n=6A306675