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A085708
Arithmetic derivative of 10^n.
4
0, 7, 140, 2100, 28000, 350000, 4200000, 49000000, 560000000, 6300000000, 70000000000, 770000000000, 8400000000000, 91000000000000, 980000000000000, 10500000000000000, 112000000000000000, 1190000000000000000, 12600000000000000000, 133000000000000000000
OFFSET
0,2
COMMENTS
a(n) = A003415(A011557(n)) = A008589(n)*A011557(n-1).
FORMULA
a(n) = 7*n*10^(n-1).
G.f.: 7*x/(10*x-1)^2.
MATHEMATICA
Table[7*n*10^(n-1), {n, 0, 20}] (* Harvey P. Dale, Jul 09 2021 *)
PROG
(Magma) [7*n*10^(n-1): n in [0..20]]; // Vincenzo Librandi, Jun 09 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Jul 19 2003
STATUS
approved