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%I #21 Mar 15 2024 12:48:49
%S 1,1,2,6,12,44,116,374,1428,5960,26016,120570,590598,3065372,16566508,
%T 92827128,542485764,3298228302,20696614200,133722820270,892046755174,
%U 6136788856858,43308637312440,313079705562778,2322726645160856
%N Number of permutations of {1..n} with the sum of squared adjacent differences <= n*(n+1)/2.
%Y Cf. A180071.
%K nonn,hard
%O 0,3
%A _R. H. Hardin_, Aug 09 2010
%E a(17)-a(18) from _Donovan Johnson_, Oct 11 2010
%E a(0)-a(1) from _Alois P. Heinz_, Sep 02 2020
%E a(19)-a(23) from _Martin Ehrenstein_, Nov 12 2023
%E a(24) from _Max Alekseyev_, Mar 15 2024