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%I #16 Mar 17 2023 15:02:00
%S 20,380,3980,39980,399980,3999980,39999980,399999980,3999999980,
%T 39999999980,399999999980,3999999999980,39999999999980,
%U 399999999999980,3999999999999980,39999999999999980,399999999999999980
%N a(n) = 4*(10^n-5).
%C Is this 20*A067272(n)?
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).
%F G.f.: 20*x*(1+8*x) / ( (10*x-1)*(x-1) ). - _R. J. Mathar_, Jan 06 2011
%F a(n) = 11*a(n-1) - 10*a(n-2). - _Wesley Ivan Hurt_, Mar 17 2023
%p A177109:=n->4*(10^n-5): seq(A177109(n), n=1..30); # _Wesley Ivan Hurt_, Feb 16 2017
%Y Cf. A067272.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Nov 15 2010
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