a(n) = a(n-1) + Sum_{k=0..n-3} a(k) for n >= 2, a(0)=1, a(1)=2.

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =6a(5) =11a(6) =19a(7) =33a(8) =58a(9) =102a(10) =179a(11) =314a(12) =551a(13) =967a(14) =1697a(15) =2978a(16) =5226a(17) =9171a(18) =16094a(19) =28243a(20) =49563a(21) =86977a(22) =152634a(23) =267854a(24) =470051a(25) =824882a(26) =1447567a(27) =2540303a(28) =4457921a(29) =7823106