a(n) = greatest k such that s(k) = n, where s = A026362.

Terms

a(0) =2a(1) =7a(2) =10a(3) =13a(4) =16a(5) =21a(6) =24a(7) =29a(8) =32a(9) =37a(10) =40a(11) =45a(12) =48a(13) =51a(14) =54a(15) =59a(16) =62a(17) =67a(18) =70a(19) =73a(20) =76a(21) =81a(22) =84a(23) =89a(24) =92a(25) =95a(26) =98a(27) =103a(28) =106a(29) =111