a(1) = a(2) = a(3) = a(4) = a(5) = 1 and for n>5: a(n) = a(n-4) + a(n-5).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =2a(7) =2a(8) =2a(9) =3a(10) =4a(11) =4a(12) =4a(13) =5a(14) =7a(15) =8a(16) =8a(17) =9a(18) =12a(19) =15a(20) =16a(21) =17a(22) =21a(23) =27a(24) =31a(25) =33a(26) =38a(27) =48a(28) =58a(29) =64