Coefficients of 1/sqrt(1-4*x-8*x^2); also, a(n) is the central coefficient of (1+2*x+3*x^2)^n.

A084609

Coefficients of 1/sqrt(1-4*x-8*x^2); also, a(n) is the central coefficient of (1+2*x+3*x^2)^n.

Terms

    a(0) =1a(1) =2a(2) =10a(3) =44a(4) =214a(5) =1052a(6) =5284a(7) =26840a(8) =137638a(9) =710828a(10) =3692140a(11) =19266920a(12) =100932220a(13) =530479640a(14) =2795917960a(15) =14771797424a(16) =78210099718a(17) =414862155980

External references