%I A099513
%S A099513 1,4,8,27,89,257,784,2421,7336,22324,68147,207549,632177,1926608,
%T A099513 5870089,17884476,54493120,166034731,505883825,1541369745,4696373312,
%U A099513 14309268413,43598614528,132839740908,404746601923,1233213978037
%N A099513 Row sums of triangle A099512, so that a(n) = Sum_{k=0..n} coefficient 
               of z^k in (1 + 3*z + z^2)^(n-[k/2]), where [k/2] is the integer floor 
               of k/2.
%F A099513 G.f.: (1+2*x-x^2)/(1-2*x-x^2-7*x^3+x^4).
%o A099513 (PARI) a(n)=sum(k=0,n,polcoeff((1+3*x+x^2+x*O(x^k))^(n-k\2),k))
%Y A099513 Cf. A099512.
%Y A099513 Sequence in context: A026085 A036720 A110132 this_sequence A104042 A117864 
               A020138
%Y A099513 Adjacent sequences: A099510 A099511 A099512 this_sequence A099514 A099515 
               A099516
%K A099513 nonn
%O A099513 0,2
%A A099513 Paul D. Hanna (pauldhanna(AT)juno.com), Oct 21 2004