a(n) = floor(sqrt(phi(w)*sigma(w)+w^2)), where w=10^n.

A065550

a(n) = floor(sqrt(phi(w)*sigma(w)+w^2)), where w=10^n.

Terms

    a(0) =13a(1) =136a(2) =1391a(3) =14030a(4) =140865a(5) =1411444a(6) =14128309a(7) =141352267a(8) =1413868217a(9) =14140409111a(10) =141412724154

External references