a(n)=ceiling( sum_{i=1..n-1} a(i)/6), a(1)=1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =2a(8) =2a(9) =2a(10) =3a(11) =3a(12) =4a(13) =4a(14) =5a(15) =6a(16) =7a(17) =8a(18) =9a(19) =11a(20) =13a(21) =15a(22) =17a(23) =20a(24) =23a(25) =27a(26) =32a(27) =37a(28) =43a(29) =50