a(n) is the least number k such that A246600(k) = n, and -1 if no such k exists.

Terms

a(0) =1a(1) =3a(2) =39a(3) =15a(4) =175a(5) =63a(6) =1275a(7) =255a(8) =1215a(9) =891a(10) =495a(11) =6975a(12) =14175a(13) =26367a(14) =13311a(15) =8127a(16) =20475a(17) =42735a(18) =95931a(19) =69615a(20) =36855a(21) =24255a(22) =404415a(23) =4095a(24) =96255a(25) =423423a(26) =253935a(27) =98175a(28) =913275a(29) =165375