a(n) = floor(((n mod 6)+1) * 10^floor((n/6)+1) / 7).

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =7a(5) =8a(6) =14a(7) =28a(8) =42a(9) =57a(10) =71a(11) =85a(12) =142a(13) =285a(14) =428a(15) =571a(16) =714a(17) =857a(18) =1428a(19) =2857a(20) =4285a(21) =5714a(22) =7142a(23) =8571a(24) =14285a(25) =28571a(26) =42857a(27) =57142a(28) =71428a(29) =85714