a(0) = ... = a(3) = 1; a(n) = Sum_{k=1..n-4} a(k) * a(n-k-4).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =0a(5) =1a(6) =2a(7) =3a(8) =3a(9) =3a(10) =5a(11) =9a(12) =15a(13) =19a(14) =24a(15) =35a(16) =59a(17) =95a(18) =137a(19) =191a(20) =280a(21) =445a(22) =706a(23) =1071a(24) =1575a(25) =2357a(26) =3663a(27) =5755a(28) =8890a(29) =13483