Coefficients of 1/(1-2*x-7*x^2)^(1/2); also, a(n) is the central coefficient of (1+x+2*x^2)^n.

A084601

Coefficients of 1/(1-2*x-7*x^2)^(1/2); also, a(n) is the central coefficient of (1+x+2*x^2)^n.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =13a(4) =49a(5) =161a(6) =581a(7) =2045a(8) =7393a(9) =26689a(10) =97285a(11) =355565a(12) =1305745a(13) =4808545a(14) =17760965a(15) =65753693a(16) =243954113a(17) =906758785a(18) =3375949829a(19) =12587460557a(20) =46995614449a(21) =175669746209a(22) =657370655045

External references