a(1) = 5, a(n+1) is the smallest multiple of a(n) using only prime digits (2,3,5,7).

A078234

a(1) = 5, a(n+1) is the smallest multiple of a(n) using only prime digits (2,3,5,7).

Terms

    a(0) =5a(1) =25a(2) =75a(3) =225a(4) =3375a(5) =57375a(6) =2352375a(7) =322275375

External references