a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4, with initial terms 0,1,3,3.

Terms

a(0) =0a(1) =1a(2) =3a(3) =3a(4) =4a(5) =8a(6) =14a(7) =21a(8) =33a(9) =55a(10) =90a(11) =144a(12) =232a(13) =377a(14) =611a(15) =987a(16) =1596a(17) =2584a(18) =4182a(19) =6765a(20) =10945a(21) =17711a(22) =28658a(23) =46368a(24) =75024a(25) =121393a(26) =196419a(27) =317811a(28) =514228a(29) =832040