A180071 Number of permutations of {1..n} with the sum of squared adjacent differences < n*(n+1)/2.
0, 1, 2, 6, 12, 24, 98, 344, 1236, 5332, 23772, 110962, 547714, 2840028, 15439466, 87299850, 512569668, 3111575102, 19577613014, 127331688104, 852129210498, 5853657714546, 41377621755100, 300511333393982, 2233952140321104
Offset: 0
Crossrefs
Cf. A180070.
Extensions
a(17)-a(18) from Donovan Johnson, Oct 11 2010
a(19) from Bert Dobbelaere, Aug 31 2020
a(0)-a(1) from Alois P. Heinz, Sep 02 2020
a(20)-a(23) from Martin Ehrenstein, Nov 12 2023
a(24) from Max Alekseyev, Mar 15 2024