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A180068
Number of permutations of 1..n with the sum of squared adjacent differences <= n*(n-1)/2.
1
2, 2, 6, 16, 34, 140, 508, 2100, 9386, 44398, 214410, 1103178, 6002116, 33772692, 196340714, 1190396084, 7486976948, 48456599516, 322526380686, 2215295406072, 15651462450174, 113259396917170
OFFSET
2,1
CROSSREFS
Cf. A180069.
Sequence in context: A336633 A001464 A067136 * A034439 A230825 A060165
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 09 2010
EXTENSIONS
a(17)-a(18) from Donovan Johnson, Oct 11 2010
a(19)-a(23) from Martin Ehrenstein, Nov 12 2023
STATUS
approved