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A099673 Partial sums of repdigits of A002280. 0
6, 72, 738, 7404, 74070, 740736, 7407402, 74074068, 740740734, 7407407400, 74074074066, 740740740732, 7407407407398, 74074074074064, 740740740740730, 7407407407407396, 74074074074074062, 740740740740740728 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

a(n) = (2/27)*(10^(n+1) - 9*n - 10). - R. Piyo (nagoya314(AT)yahoo.com), Dec 10 2004

EXAMPLE

6 + 66 + 666 + 6666 + 66666 = a(5) = 74070.

MATHEMATICA

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

Table[6/9*Sum[10^i - 1, {i, n}], {n, 18}] (* Robert G. Wilson v, Nov 20 2004 *)

CROSSREFS

Cf. A057932, A002275-A002283, A099669-A099675.

Sequence in context: A059410 A238103 A200978 * A105928 A186665 A007031

Adjacent sequences:  A099670 A099671 A099672 * A099674 A099675 A099676

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Nov 17 2004

STATUS

approved

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Last modified February 26 08:15 EST 2020. Contains 332277 sequences. (Running on oeis4.)