a(n) is the least odd number k such that A376615(k) = n, or -1 if no such number exists.

A376619

a(n) is the least odd number k such that A376615(k) = n, or -1 if no such number exists.

Terms

    a(0) =3a(1) =21a(2) =345a(3) =10625a(4) =74375a(5) =860625a(6) =84189105a(7) =1599592995a(8) =23993894925

External references