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 A099669 Partial sums of repdigits of A002276. 7

%I

%S 2,24,246,2468,24690,246912,2469134,24691356,246913578,2469135800,

%T 24691358022,246913580244,2469135802466,24691358024688,

%U 246913580246910,2469135802469132,24691358024691354,246913580246913576,2469135802469135798,24691358024691358020

%N Partial sums of repdigits of A002276.

%H Matthew House, <a href="/A099669/b099669.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (12,-21,10).

%F a(n) = (2/81)*(10^(n+1) - 9*n - 10). - R. Piyo (nagoya314(AT)yahoo.com), Dec 10 2004

%F a(n) = 12*a(n-1) - 21*a(n-2) + 10*a(n-3). - _Matthew House_, Jun 30 2016

%F G.f.: 2*x/((1 - x)^2*(1 - 10*x)). - _Ilya Gutkovskiy_, Jun 30 2016

%e 2 + 22 + 222 + 2222 = a(4) = 2468.

%p A099669:=n->(2/81)*(10^(n+1) - 9*n - 10): seq(A099669(n), n=1..30); # _Wesley Ivan Hurt_, Apr 18 2017

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

%t Table[2/9*Sum[10^i - 1, {i, n}], {n, 18}] (* _Robert G. Wilson v_, Nov 20 2004 *)

%Y Cf. A057932, A002275-A002283.

%K nonn,easy

%O 1,1

%A _Labos Elemer_, Nov 17 2004

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Last modified March 30 16:16 EDT 2020. Contains 333127 sequences. (Running on oeis4.)