OFFSET
0,4
REFERENCES
D. E. Knuth, TAOCP, Section 7.2.1.6, Problem 34.
FORMULA
(n*(n-1)/2)! * Product( (2*i-1)^(n-i),i=1..n-1).
MAPLE
f:=n-> (n*(n-1)/2)! * mul( (2*i-1)^(n-i), i=1..n-1);
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 15 2006
STATUS
approved