A259785 Number of permutations p of [2n] with no fixed points where the maximal displacement of an element equals n.

1, 1, 3, 44, 1285, 59963, 4113244, 389384029, 48627012403, 7743988554848, 1531612782695209, 368303149768896363, 105818590347793426632

Offset: 0

Author

Alois P. Heinz, Jul 05 2015

Keywords

• nonn
• more

Examples

			a(0) = 1: (the empty permutation).
a(1) = 1: 21.
a(2) = 3: 2413, 3142, 3412.
a(3) = 44: 214563, 215643, 216345, ..., 451623, 452163, 456123.
		

Crossrefs

Cf. A259784.

Formula

a(n) = A259784(2n,n).