A085708 Arithmetic derivative of 10^n.

0, 7, 140, 2100, 28000, 350000, 4200000, 49000000, 560000000, 6300000000, 70000000000, 770000000000, 8400000000000, 91000000000000, 980000000000000, 10500000000000000, 112000000000000000, 1190000000000000000, 12600000000000000000, 133000000000000000000

Offset: 0

Author

Reinhard Zumkeller, Jul 19 2003

Keywords

• nonn
• easy

Comments

a(n) = A003415(A011557(n)) = A008589(n)*A011557(n-1).

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..100
• Index entries for linear recurrences with constant coefficients, signature (20,-100).

Crossrefs

Cf. A001787, A003415, A008589, A011557, A027471.

Programs

Magma

[7*n*10^(n-1): n in [0..20]]; // Vincenzo Librandi, Jun 09 2011

Mathematica

Table[7*n*10^(n-1),{n,0,20}] (* Harvey P. Dale, Jul 09 2021 *)

Formula

a(n) = 7*n*10^(n-1).

G.f.: 7*x/(10*x-1)^2.