Intersection of A025487 and A007531.

A386951

Intersection of A025487 and A007531.

Terms

    a(0) =6a(1) =24a(2) =60a(3) =120a(4) =210a(5) =720a(6) =3360a(7) =9240a(8) =166320a(9) =970200a(10) =43243200

External references