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%I #11 May 17 2023 12:17:48
%S 1,2,23,334,4445,55556,666667,7777778,88888889,1000000000,11111111111,
%T 122222222222,1333333333333,14444444444444,155555555555555,
%U 1666666666666666,17777777777777777,188888888888888888
%N a(n) = (n*10^n - n + 9)/9.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (22,-141,220,-100).
%F G.f.: ( 1-20*x+120*x^2-110*x^3 ) / ( (10*x-1)^2*(x-1)^2 ). - _R. J. Mathar_, Feb 14 2015
%F a(n) = 22*a(n-1) - 141*a(n-2) + 220*a(n-3) - 100*a(n-4). - _Wesley Ivan Hurt_, May 17 2023
%Y Cf. A091686.
%K easy,nonn
%O 0,2
%A _Paul Barry_, Jan 29 2004