OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..58 [Terms 0 through 25 were computed by G. C. Greubel]
FORMULA
a(n) = variations(2^n-1,n-1).
a(n) = (2^n-1)!/(2^n-n)!. - N. J. A. Sloane, Feb 21 2009
MAPLE
a:= n-> (t-> mul(j, j=t-n+1..t-1))(2^n):
seq(a(n), n=0..15); # Alois P. Heinz, Jan 30 2016
MATHEMATICA
Table[(2^n - 1)!/(2^n - n)!, {n, 0, 20}] (* G. C. Greubel, Jan 30 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Csabay Karoly (csabay58(AT)gmail.com), Oct 26 2008; entry revised Feb 19 2009, Apr 21 2010
EXTENSIONS
More terms from N. J. A. Sloane, Feb 21 2009
STATUS
approved