a(0)=0, a(1)=a(2)=a(3)=a(4)=1; thereafter, a(n) = Sum_{k=1..5} a(n-k-(a(n-k) mod 5)).

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =4a(7) =5a(8) =9a(9) =9a(10) =11a(11) =19a(12) =23a(13) =27a(14) =45a(15) =87a(16) =105a(17) =205a(18) =401a(19) =587a(20) =747a(21) =1121a(22) =1763a(23) =2145a(24) =4085a(25) =7965a(26) =15529a(27) =16545a(28) =32503a(29) =38323