%I A000708 M4188 N1745
%S A000708 1,1,0,1,6,29,150,841,5166,34649,252750,1995181,16962726,154624469,
%T A000708 1505035350,15583997521,171082318686,1985148989489,24279125761950,
%U A000708 312193418011861,4210755676649046,59445878286889709,876726137720576550
%N A000708 Number of quasi-alternating permutations of length n.
%D A000708 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A000708 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A000708 E. Netto, Lehrbuch der Combinatorik. 2nd ed., Teubner, Leipzig, 1927, 
               p. 113.
%D A000708 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 261.
%F A000708 a(n)=|A000111(n+1)-2*A000111(n)| . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), 
               Jan 13 2007
%p A000708 seq(i!*coeff(series(((tan(t)+sec(t))^2-4*(tan(t)+sec(t)))/2,t,35),t,i),
               i=2..24);
%Y A000708 Equals (1/2)*A001758. A diagonal of A008970.
%Y A000708 Sequence in context: A125785 A108982 A059724 this_sequence A027248 A020090 
               A020036
%Y A000708 Adjacent sequences: A000705 A000706 A000707 this_sequence A000709 A000710 
               A000711
%K A000708 nonn
%O A000708 0,5
%A A000708 N. J. A. Sloane (njas(AT)research.att.com).
%E A000708 More terms, Maple code from Barbara Haas Margolius (margolius(AT)math.csuohio.edu) 
               3/12/01
%E A000708 Corrected and extended by T. D. Noe (noe(AT)sspectra.com), Oct 25 2006