Concatenation of n and n + 5 or {n,n+5}.

Terms

a(0) =16a(1) =27a(2) =38a(3) =49a(4) =510a(5) =611a(6) =712a(7) =813a(8) =914a(9) =1015a(10) =1116a(11) =1217a(12) =1318a(13) =1419a(14) =1520a(15) =1621a(16) =1722a(17) =1823a(18) =1924a(19) =2025a(20) =2126a(21) =2227a(22) =2328a(23) =2429a(24) =2530a(25) =2631a(26) =2732a(27) =2833a(28) =2934a(29) =3035