a(n) is the smallest number whose name in UK English contains n consonants.

Terms

a(0) =1a(1) =2a(2) =3a(3) =12a(4) =13a(5) =22a(6) =23a(7) =300a(8) =101a(9) =102a(10) =103a(11) =112a(12) =113a(13) =122a(14) =123a(15) =223a(16) =323a(17) =1112a(18) =1113a(19) =1122a(20) =1123a(21) =1223a(22) =1323a(23) =2323a(24) =3323a(25) =12323a(26) =13323a(27) =22323a(28) =23323a(29) =101223