Append d digits d after each digit d in decimal expansion of n.

Terms

a(0) =0a(1) =11a(2) =222a(3) =3333a(4) =44444a(5) =555555a(6) =6666666a(7) =77777777a(8) =888888888a(9) =9999999999a(10) =110a(11) =1111a(12) =11222a(13) =113333a(14) =1144444a(15) =11555555a(16) =116666666a(17) =1177777777a(18) =11888888888a(19) =119999999999a(20) =2220a(21) =22211a(22) =222222a(23) =2223333a(24) =22244444a(25) =222555555a(26) =2226666666