a(n) = least k such that the remainder when 18^k is divided by k is n.

Terms

a(0) =17a(1) =14a(2) =5a(3) =7a(4) =13a(5) =106a(6) =11a(7) =158a(8) =927a(9) =314a(10) =6767a(11) =15a(12) =724317787a(13) =62a(14) =21a(15) =20a(16) =407a(17) =19a(18) =319a(19) =38a(20) =39a(21) =302a(22) =150698261a(23) =30a(24) =1055599a(25) =298a(26) =129a(27) =74