Second-order Fibonacci numbers.

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =5a(5) =10a(6) =18a(7) =33a(8) =59a(9) =105a(10) =185a(11) =324a(12) =564a(13) =977a(14) =1685a(15) =2895a(16) =4957a(17) =8462a(18) =14406a(19) =24465a(20) =41455a(21) =70101a(22) =118321a(23) =199368a(24) =335400a(25) =563425a(26) =945193a(27) =1583643a(28) =2650229a(29) =4430290