A249392 The number of down-up permutations of [n] where adjacent elements differ by at least 5.

1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 32, 1088, 17280, 293832, 4004352, 57687080, 773838336, 10900027949, 151388845568, 2200665880514, 32321771402240, 495575856116168, 7760560549644288, 126552637539515688

Offset: 0

Author

R. J. Mathar, Oct 27 2014

Keywords

• nonn
• more

Crossrefs

Cf. A245377 (at least 2), A249390 (at least 3), A249391 (at least 4), A249393 (at least 6), A179958 (non-alternating)

Extensions

a(17)-a(21) from Alois P. Heinz, Oct 27 2014

a(22)-a(24) from Max Alekseyev, Feb 24 2024