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A029576 Number of permutations of an n-set containing a 9-cycle. 2
0, 0, 0, 0, 0, 0, 0, 0, 0, 40320, 403200, 4435200, 53222400, 691891200, 9686476800, 145297152000, 2324754432000, 39520825344000, 671854030848000, 12765226586112000, 255304531722240000, 5361395166167040000, 117950693655674880000, 2712865954080522240000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,10
LINKS
FORMULA
a(n) = n!*(1 - Sum_{k=0..floor(n/9)} (-1)^k/(k!*9^k); a(n)/n! is asymptotic to 1-e^(-1/9).
E.g.f.: (1-exp(-x^9/9))/(1-x). - Alois P. Heinz, Oct 11 2017
Conjectures from Stéphane Rézel, Nov 24 2019: (Start)
Recurrence: a(n) = n*a(n-1), for n > 9 and n !== 0 (mod 9);
for k > 1, a(9*k) = a(9*k-1)*S(k)/S(k-1) where S(k) = 9*k*S(k-1) - (-1)^k with S(1) = 1.
(End)
PROG
(PARI) a(n) = n! * (1 - sum(k=0, floor(n/9), (-1)^k/(k!*9^k) ) ); \\ Stéphane Rézel, Nov 24 2019
CROSSREFS
Column k=9 of A293211.
Sequence in context: A239035 A179734 A061123 * A179966 A133068 A254081
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)