a(n) = 10^n*(3 + 7*10^n) + 7.

A171766

a(n) = 10^n*(3 + 7*10^n) + 7.

Terms

    a(0) =17a(1) =737a(2) =70307a(3) =7003007a(4) =700030007a(5) =70000300007

External references