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A261427
Number of permutations p of [7n] without fixed points such that p^7 = Id.
3
1, 720, 889574400, 24825530695680000, 5290995845684330496000000, 5123434663327851951402516480000000, 16586604100059403377645257954741452800000000, 146550752102252281868362306608987740351496192000000000
OFFSET
0,2
LINKS
FORMULA
a(n) = (7n)! * [x^(7n)] exp(x^7/7).
MAPLE
a:= proc(n) option remember; `if`(n=0, 1,
mul(7*n-i, i=1..6)*a(n-1))
end:
seq(a(n), n=0..10);
CROSSREFS
7-section of column k=7 of A261430.
Cf. A053497.
Sequence in context: A208192 A258927 A195390 * A210280 A003926 A172621
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 18 2015
STATUS
approved