a(1) = a(2) = 1; a(n) = ( Sum_{i|(n-1)} a(i) ) + Sum_{j|(n-2)} a(j).

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =12a(5) =21a(6) =39a(7) =66a(8) =114a(9) =192a(10) =324a(11) =531a(12) =888a(13) =1452a(14) =2382a(15) =3891a(16) =6363a(17) =10329a(18) =16833a(19) =27303a(20) =44349a(21) =71907a(22) =116625a(23) =188859a(24) =306114a(25) =495615a(26) =802632a(27) =1299255a(28) =2103504a(29) =3404259