17572114

Appears in sequences

• Number of partial permutations of an n-set; number of n X n binary matrices with at most one 1 in each row and column.at n=9A002720
• Denominators of continued fraction for alternating factorial.at n=18A056953
• Lower triangular matrix, read by rows: T(i,j) = number of ways i seats can be occupied by any number k (0<=k<=j<=i) of persons.at n=44A086885
• Triangle read by rows: Sum_{j=0..k} binomial(n, j)*binomial(k, j)*j!.at n=54A176120
• Number of ways to place k non-attacking bishops on an n x n toroidal chessboard, summed over all k >= 0.at n=8A215943
• Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where T(n,k) = Sum_{j=0..n} j^k * (n-j)! * binomial(n,j)^2.at n=54A341200