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A126634 a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks the digits 1,2,3,4 and at least one of digits 5,6,7,8,9.

%I A126634 #13 Apr 01 2018 09:43:54
%S A126634 6,36,216,1296,7656,44136,248016,1362096,7338456,38927736,203958816,
%T A126634 1058224896,5448329256,27880971336,141993797616,720419919696,
%U A126634 3644189320056,18390164454936,92630272564416,465876904526496,2340309918950856,11745320884258536
%N A126634 a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks the digits 1,2,3,4 and at least one of digits 5,6,7,8,9.
%H A126634 Colin Barker, <a href="/A126634/b126634.txt">Table of n, a(n) for n = 1..1000</a>
%H A126634 Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>
%H A126634 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (15,-85,225,-274,120).
%F A126634 a(n) = 5*5^n-10*4^n+10*3^n-5*2^n+1.
%F A126634 G.f.: -6*x*(20*x^4-39*x^3+31*x^2-9*x+1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)). - _Colin Barker_, Feb 22 2015
%p A126634 f:=n->5*5^n-10*4^n+10*3^n-5*2^n+1;
%t A126634 LinearRecurrence[{15,-85,225,-274,120},{6,36,216,1296,7656},30] (* _Harvey P. Dale_, Apr 01 2018 *)
%o A126634 (PARI) Vec(-6*x*(20*x^4-39*x^3+31*x^2-9*x+1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)) + O(x^100)) \\ _Colin Barker_, Feb 22 2015
%Y A126634 Cf. A125630, A125948, A125947, A125946, A125945, A125910, A125909, A125908, A125880, A125897, A125904, A125858.
%K A126634 nonn,base,easy
%O A126634 1,1
%A A126634 Aleksandar M. Janjic and _Milan Janjic_, Feb 08 2007