Nonzero digits not used in n.

Terms

a(0) =123456789a(1) =23456789a(2) =13456789a(3) =12456789a(4) =12356789a(5) =12346789a(6) =12345789a(7) =12345689a(8) =12345679a(9) =12345678a(10) =23456789a(11) =23456789a(12) =3456789a(13) =2456789a(14) =2356789a(15) =2346789a(16) =2345789a(17) =2345689a(18) =2345679a(19) =2345678a(20) =13456789a(21) =3456789a(22) =13456789a(23) =1456789a(24) =1356789a(25) =1346789a(26) =1345789