A345655 a(n) is the number of permutations w of [n] with no w(i)+1 == w(i+1) (mod n) that are not simply cyclic permutations of the numbers 1 to n in backwards order.

0, 0, 0, 0, 35, 210, 1596, 12992, 118863, 1202870, 13361392, 161638752, 2115684259, 29792671818, 449145795900, 7217975402752, 123180993414207, 2224874726830638, 42402252681323840, 850380681002034880, 17902407539998807875, 394741856473979171586, 9097740802923890621468

Offset

1,5

Links

Table of n, a(n) for n=1..23.

Formula

a(n) = A167760(n) - n for n >= 3.

a(n) = max(0, A167760(n) - n).

Crossrefs

Cf. A167760.

Sequence in context: A219942 A232713 A007329 * A101628 A064013 A240137

Adjacent sequences: A345652 A345653 A345654 * A345656 A345657 A345658

Keyword

nonn

Author

J. Lowell, Jun 21 2021

Status

approved