a(1)=1, a(n) = least odd triangular number which is a proper multiple of a(n-1).

A088108

a(1)=1, a(n) = least odd triangular number which is a proper multiple of a(n-1).

Terms

    a(0) =1a(1) =3a(2) =15a(3) =45a(4) =1035a(5) =85905a(6) =1116765a(7) =657774585

External references