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A151579 Number of permutations of 1..n arranged in a circle with exactly 6 adjacent element pairs in decreasing order. 2
0, 7, 960, 38637, 882340, 14413894, 188690976, 2112659718, 21078701112, 192648942945, 1644431982848, 13295963811083, 102911255502876, 768689550213368, 5575887557096640, 39473882067826332, 273820542615005232, 1867156445048432043, 12548621876834960064 (list; graph; refs; listen; history; text; internal format)
OFFSET

6,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 6..500

FORMULA

From Andrew Howroyd, May 05 2020: (Start)

a(n) = n*A000514(n-1).

a(n) = n*(6^(n-1) - n*5^(n-1) + binomial(n,2)*4^(n-1) - binomial(n,3)*3^(n-1) + binomial(n,4)*2^(n-1) - binomial(n,5)). (End)

PROG

(PARI) a(n) = {n*(6^(n-1) - n*5^(n-1) + binomial(n, 2)*4^(n-1) - binomial(n, 3)*3^(n-1) + binomial(n, 4)*2^(n-1) - binomial(n, 5))} \\ Andrew Howroyd, May 05 2020

CROSSREFS

Column k=6 of A334218.

Cf. A000514.

Sequence in context: A068728 A028990 A304396 * A024098 A172918 A286913

Adjacent sequences:  A151576 A151577 A151578 * A151580 A151581 A151582

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 21 2009

EXTENSIONS

Terms a(17) and beyond from Andrew Howroyd, May 05 2020

STATUS

approved

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Last modified July 2 08:02 EDT 2020. Contains 335398 sequences. (Running on oeis4.)