Coefficients of 1/sqrt(1 - 2*x - 11*x^2); also, a(n) is the central coefficient of (1 + x + 3*x^2)^n.

A084603

Coefficients of 1/sqrt(1 - 2*x - 11*x^2); also, a(n) is the central coefficient of (1 + x + 3*x^2)^n.

Terms

    a(0) =1a(1) =1a(2) =7a(3) =19a(4) =91a(5) =331a(6) =1441a(7) =5797a(8) =24739a(9) =103411a(10) =441397a(11) =1876777a(12) =8047909a(13) =34533253a(14) =148803487a(15) =642228139a(16) =2778852979a(17) =12043194163a(18) =52286516821a(19) =227323871929a(20) =989675651041

External references