Arithmetic derivative of 10^n.

Terms

a(0) =0a(1) =7a(2) =140a(3) =2100a(4) =28000a(5) =350000a(6) =4200000a(7) =49000000a(8) =560000000a(9) =6300000000a(10) =70000000000a(11) =770000000000