OFFSET
1,6
COMMENTS
Number of permutations of n elements with 6 odd displacements.
Column 4 of A226288.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
MATHEMATICA
Table[Floor[n/2]!Floor[(n+1)/2]!Binomial[Floor[n/2], 3]Binomial[Floor[ (n+1)/2], 3], {n, 30}] (* Harvey P. Dale, Dec 12 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, connection of formula with combinatoric problem via N. J. A. Sloane in the Sequence Fans Mailing List, Jun 02 2013
STATUS
approved