a(n) = 1 + Sum_{k=1..n-5} a(k) * a(n-k-5).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =3a(8) =4a(9) =5a(10) =6a(11) =8a(12) =12a(13) =18a(14) =26a(15) =36a(16) =49a(17) =69a(18) =101a(19) =150a(20) =221a(21) =320a(22) =460a(23) =667a(24) =981a(25) =1456a(26) =2161a(27) =3191a(28) =4698a(29) =6932