Column 0 of triangle A118045; also equals a bisection of A118033, which is column 0 of A118032.

Terms

a(0) =1a(1) =3a(2) =9a(3) =26a(4) =73a(5) =191a(6) =500a(7) =1234a(8) =3051a(9) =7201a(10) =16995a(11) =38818a(12) =88022a(13) =195800a(14) =429962a(15) =936404a(16) =1995551a(17) =4251251a(18) =8823913a(19) =18497448a(20) =37518051a(21) =77131335a(22) =152995870a(23) =310503756a(24) =605012792a(25) =1207121646a(26) =2308671442a(27) =4558228440a(28) =8598558052