%I A091596
%S A091596 0,1,2,5,12,27,62,137,304,663,1442,3109,6676,14259,30342,64321,135928,
%T A091596 286415,601962,1262173,2640860,5514731,11495502,23923065,49710272,
%U A091596 103148807,213754162,442421397,914668964,1888990243,3897285142
%N A091596 Expansion of x(1-2x^2)/(1-x-2x^2)^2.
%C A091596 Second column of A091595.
%F A091596 a(n) := sum{k=0..floor((n-1)/2), binomial(n-k-1, k)2^k }; a(n)=2a(n-1)+3a(n-2)-4a(n-3)-4a(n-4).
%F A091596 a(n)=(1/9)*(-1)^n*n-(8/27)*(-1)^n+(8/27)*2^n+(1/9)*2^n*n, with n>=0 - 
               Paolo P. Lava (ppl(AT)spl.at), Jun 10 2008
%Y A091596 Sequence in context: A116712 A000102 A086589 this_sequence A077863 A018009 
               A128096
%Y A091596 Adjacent sequences: A091593 A091594 A091595 this_sequence A091597 A091598 
               A091599
%K A091596 easy,nonn
%O A091596 0,3
%A A091596 Paul Barry (pbarry(AT)wit.ie), Jan 23 2004