A375022 Number of permutations of n (distinct) elements from [2n] without consecutive adjacent values.

1, 2, 6, 48, 650, 11604, 253890, 6572176, 196467642, 6660672060, 252504829346, 10584157180920, 486052773276954, 24267623565599428, 1308816525199710210, 75828568345500497184, 4696852810090223180090, 309727816544792336406156, 21664419864179709448539042

Offset: 0

Author

Alois P. Heinz, Aug 04 2024

Keywords

• nonn

Examples

			a(0) = 1: the empty permutation.
a(1) = 2: 1, 2.
a(2) = 6: 13, 14, 24, 31, 41, 42.
a(3) = 48: 135, 136, 142, 146, 152, 153, 162, 163, 164, 241, 246, 251, 253, 261, 263, 264, 314, 315, 316, 351, 352, 361, 362, 364, 413, 415, 416, 425, 426, 461, 462, 463, 513, 514, 516, 524, 526, 531, 536, 613, 614, 615, 624, 625, 631, 635, 641, 642.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..366

Crossrefs

Cf. A338526.

Formula

a(n) = A338526(2n,n).