%I A002867 M2035 N0806
%S A002867 1,2,12,72,720,7200,100800,1411200,25401600,457228800,10059033600,
%T A002867 221298739200,5753767219200,149597947699200,4487938430976000,
%U A002867 134638152929280000,4577697199595520000,155641704786247680000
%N A002867 C(n,[n/2])*(n+1)!.
%D A002867 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A002867 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A002867 T. S. Motzkin, Sorting numbers ...: for a link to this paper see A000262.
%D A002867 T. S. Motzkin, Sorting numbers for cylinders and other classification 
               numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, 
               pp. 167-176.
%F A002867 E.g.f.: 1/(sqrt(1+2x)*(1-2x)^(3/2))=1/(sqrt(1-4x^2)*(1-2x)); - Paul Barry 
               (pbarry(AT)wit.ie), Jul 22 2005
%Y A002867 2^n * A000246(n+1).
%Y A002867 Sequence in context: A052833 A144086 A005443 this_sequence A130426 A002397 
               A163085
%Y A002867 Adjacent sequences: A002864 A002865 A002866 this_sequence A002868 A002869 
               A002870
%K A002867 nonn,easy
%O A002867 0,2
%A A002867 N. J. A. Sloane (njas(AT)research.att.com).
%E A002867 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 10 2000