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A180237
Number of lexicographically ordered pairs of permutations of 0..2n-2 such that their sum mod 2n-1 is also a permutation of 0..2n-2
0
1, 12, 960, 337680, 367597440, 755465356800, 3208061483827200, 23775433137840384000
OFFSET
1,2
COMMENTS
Numbers for permutations of 0..2n-1 are zero.
CROSSREFS
Sequence in context: A114371 A047802 A278705 * A079916 A204327 A370313
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 18 2010
STATUS
approved