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A099671 Partial sums of repdigits of A002278. 0
4, 48, 492, 4936, 49380, 493824, 4938268, 49382712, 493827156, 4938271600, 49382716044, 493827160488, 4938271604932, 49382716049376, 493827160493820, 4938271604938264, 49382716049382708, 493827160493827152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

FORMULA

a(n) = (4/81)*(10^(n+1) - 9*n - 10). - R. Piyo (nagoya314(AT)yahoo.com), Dec 10 2004

From Chai Wah Wu, Feb 28 2018: (Start)

a(n) = 12*a(n-1) - 21*a(n-2) + 10*a(n-3) for n > 3.

G.f.: 4*x/((1 - x)^2*(1 - 10*x)). (End)

EXAMPLE

4 + 44 + 444 + 4444 + 44444 = a(5) = 49380.

MATHEMATICA

<<NumberTheory`NumberTheoryFunctions` Table[{k, Table[Apply[Plus, Table[k*(10^n-1)/9, {n, 1, m}]], {m, 1, 35}]}, {k, 1, 9}]

Table[4/9*Sum[10^i - 1, {i, n}], {n, 18}] (* Robert G. Wilson v, Nov 20 2004 *)

CROSSREFS

Cf. A057932, A002275-A002283.

Sequence in context: A264727 A283049 A159903 * A196963 A220325 A265419

Adjacent sequences:  A099668 A099669 A099670 * A099672 A099673 A099674

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Nov 17 2004

STATUS

approved

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Last modified February 17 12:10 EST 2020. Contains 331996 sequences. (Running on oeis4.)