Number of numbers below 10^n with nonzero multiplicative digital root 7.

A051827

Number of numbers below 10^n with nonzero multiplicative digital root 7.

Terms

    a(0) =1a(1) =4a(2) =18a(3) =104a(4) =770a(5) =7188a(6) =71267a(7) =668712a(8) =5784858a(9) =46456730a(10) =351209716a(11) =2538926040a(12) =17934291011a(13) =128545882129a(14) =994784980860

External references