OFFSET
0,5
COMMENTS
a(n) = 0 iff n == 2,3 (mod 4).
LINKS
H. A. Shah Ali, Problem 10964, Amer. Math. Monthly, 109 (2002), 759.
FORMULA
a(n) = A125183(n,n). - Alois P. Heinz, Feb 16 2019
EXAMPLE
a(8) = 32, since the following 32 permutations of {12345678} and no others, have the required property:
(87265314)(87361542)(87362514)(87364215)(87514632)(87531642)(87532614)
(87541362)(83765142)(85724613)(84752613)(85743162)(86275413)(86374152)
(86357142)(86542713)(48753621)(68275431)(68374251)(58376421)(58473621)
(68357241)(68542731)(58643721)(73865241)(75824631)(74852631)(75843261)
(73685421)(75386421)(75483621)(76358421).
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Reiner Martin, Oct 15 2002
EXTENSIONS
Extended and edited by John W. Layman, Oct 05 2004
a(17)-a(27) from Al Zimmermann, Aug 03 2007
a(28) through a(31) from Al Zimmermann, Aug 22 2007
a(0)=1 prepended by Alois P. Heinz, Feb 16 2019
STATUS
approved