a(n) = ceiling( Sum_{i=1..n-1} a(i)/5 ), a(1)=1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =2a(8) =2a(9) =3a(10) =3a(11) =4a(12) =5a(13) =6a(14) =7a(15) =8a(16) =10a(17) =12a(18) =14a(19) =17a(20) =21a(21) =25a(22) =30a(23) =36a(24) =43a(25) =52a(26) =62a(27) =74a(28) =89a(29) =107