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.
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.
Terms
- a(0) =1a(1) =4a(2) =8a(3) =27a(4) =89a(5) =257a(6) =784a(7) =2421a(8) =7336a(9) =22324a(10) =68147a(11) =207549a(12) =632177a(13) =1926608a(14) =5870089a(15) =17884476a(16) =54493120a(17) =166034731a(18) =505883825a(19) =1541369745a(20) =4696373312a(21) =14309268413a(22) =43598614528a(23) =132839740908a(24) =404746601923
External references
- oeis: A099513