%I A007911
%S A007911 1,1,5,7,33,57,279,561,2895,6555,35685,89055,509985,1381905,8294895,
%T A007911 24137505,151335135,468934515,3061162125,10033419375,68000295825,
%U A007911 234484536825,1645756410375,5943863027025,43105900812975
%N A007911 (n-1)!!-(n-2)!!.
%D A007911 S. P. Hurd and J. S. McCranie, Quantum factorials. Proceedings of the 
               Twenty-fifth Southeastern International Conference on Combinatorics, 
               Graph Theory and Computing (Boca Raton, FL, 1994). Congr. Numer. 
               104 (1994), 19-24.
%H A007911 T. D. Noe, <a href="b007911.txt">Table of n, a(n) for n=3..100</a>
%p A007911 P:=proc(n) local i,j,k,w; for i from 1 by 1 to n do k:=i; w:=i-2; while 
               w>0 do k:=k*w; w:=w-2; od; j:=i+1; w:=i-1; while w>0 do j:=j*w; w:=w-2; 
               od; print(j-k); od; end: P(100); - Paolo P. Lava (ppl(AT)spl.at), 
               Jun 14 2007
%Y A007911 Cf. A007912.
%Y A007911 Sequence in context: A090935 A153414 A104815 this_sequence A066172 A018353 
               A081851
%Y A007911 Adjacent sequences: A007908 A007909 A007910 this_sequence A007912 A007913 
               A007914
%K A007911 nonn,easy
%O A007911 3,3
%A A007911 J. H. Conway (conway(AT)math.princeton.edu)