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A261427 Number of permutations p of [7n] without fixed points such that p^7 = Id. 3

%I #7 Aug 18 2015 09:06:16

%S 1,720,889574400,24825530695680000,5290995845684330496000000,

%T 5123434663327851951402516480000000,

%U 16586604100059403377645257954741452800000000,146550752102252281868362306608987740351496192000000000

%N Number of permutations p of [7n] without fixed points such that p^7 = Id.

%H Alois P. Heinz, <a href="/A261427/b261427.txt">Table of n, a(n) for n = 0..73</a>

%F a(n) = (7n)! * [x^(7n)] exp(x^7/7).

%p a:= proc(n) option remember; `if`(n=0, 1,

%p mul(7*n-i, i=1..6)*a(n-1))

%p end:

%p seq(a(n), n=0..10);

%Y 7-section of column k=7 of A261430.

%Y Cf. A053497.

%K nonn

%O 0,2

%A _Alois P. Heinz_, Aug 18 2015

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Last modified September 9 01:17 EDT 2024. Contains 375759 sequences. (Running on oeis4.)