a(n) = (n+1)*F(n), F(n) = Fibonacci numbers A000045.

Terms

a(0) =0a(1) =2a(2) =3a(3) =8a(4) =15a(5) =30a(6) =56a(7) =104a(8) =189a(9) =340a(10) =605a(11) =1068a(12) =1872a(13) =3262a(14) =5655a(15) =9760a(16) =16779a(17) =28746a(18) =49096a(19) =83620a(20) =142065a(21) =240812a(22) =407353a(23) =687768a(24) =1159200a(25) =1950650a(26) =3277611a(27) =5499704a(28) =9216519a(29) =15426870