a(n) = floor(10^n/7^n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =4a(5) =5a(6) =8a(7) =12a(8) =17a(9) =24a(10) =35a(11) =50a(12) =72a(13) =103a(14) =147a(15) =210a(16) =300a(17) =429a(18) =614a(19) =877a(20) =1253a(21) =1790a(22) =2557a(23) =3653a(24) =5219a(25) =7456a(26) =10652a(27) =15217a(28) =21739a(29) =31056