A180070 Number of permutations of {1..n} with the sum of squared adjacent differences <= n*(n+1)/2.
1, 1, 2, 6, 12, 44, 116, 374, 1428, 5960, 26016, 120570, 590598, 3065372, 16566508, 92827128, 542485764, 3298228302, 20696614200, 133722820270, 892046755174, 6136788856858, 43308637312440, 313079705562778, 2322726645160856
Offset: 0
Crossrefs
Cf. A180071.
Extensions
a(17)-a(18) from Donovan Johnson, Oct 11 2010
a(0)-a(1) from Alois P. Heinz, Sep 02 2020
a(19)-a(23) from Martin Ehrenstein, Nov 12 2023
a(24) from Max Alekseyev, Mar 15 2024