a(n) = smallest k such that A109671(k)=n, or -1 if n does not appear in A109671.

Terms

a(0) =1a(1) =3a(2) =7a(3) =39a(4) =17a(5) =15a(6) =169a(7) =33a(8) =31a(9) =135a(10) =313a(11) =231a(12) =337a(13) =1257a(14) =113a(15) =1341a(16) =65a(17) =63a(18) =1043a(19) =1077a(20) =937a(21) =4137a(22) =625a(23) =225a(24) =673a(25) =129a(26) =127a(27) =519a(28) =2057a(29) =903