A107762 Number of permutations of (1,3,5,7,9,...,2n-1) in which every pair of adjacent numbers as well as the first and the last entries are relatively prime.

1, 2, 6, 24, 60, 432, 3360, 6912, 86400, 1080000, 3432000, 57542400, 601810560, 3374784000, 71391196800, 1506917744640, 8134703216640, 87731370397440, 2330058011258880, 15991083879321600, 484342868413071360

Offset

1,2

Comments

Odd analog of A102381. Equals n*A107763(n).

Links

Table of n, a(n) for n=1..21.

Crossrefs

Cf. A076220, A086595, A102381, A107761, A107763.

Sequence in context: A189566 A178009 A357249 * A253901 A027562 A236625

Adjacent sequences: A107759 A107760 A107761 * A107763 A107764 A107765

Keyword

nonn

Author

Ray Chandler, Jun 11 2005

Extensions

More terms from Max Alekseyev, Jun 11 2005

Status

approved