a(n) = A047848(7,n).

Terms

a(0) =1a(1) =2a(2) =12a(3) =112a(4) =1112a(5) =11112a(6) =111112a(7) =1111112a(8) =11111112a(9) =111111112a(10) =1111111112a(11) =11111111112a(12) =111111111112