a(n) = Sum_{k=0..floor(n/5)} C(n-4k,k+1).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =7a(7) =10a(8) =14a(9) =19a(10) =25a(11) =33a(12) =44a(13) =59a(14) =79a(15) =105a(16) =139a(17) =184a(18) =244a(19) =324a(20) =430a(21) =570a(22) =755a(23) =1000a(24) =1325a(25) =1756a(26) =2327a(27) =3083a(28) =4084a(29) =5410