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%I #12 Jun 13 2015 00:52:18
%S 9,81,723,6381,55539,475461,3993243,32857101,264890019,2094889941,
%T 16282118763,124625344221,941303216499,7029057066021,51980086628283,
%U 381227207181741,2776407821318979,20100192515299701,144786930345697803,1038495372200033661
%N a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks the digit 1, at least one of digits 2,3,4 and at least one of digits 5,6,7,8,9.
%H Colin Barker, <a href="/A125910/b125910.txt">Table of n, a(n) for n = 1..1000</a>
%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (28,-322,1960,-6769,13132,-13068,5040).
%F a(n) = 15*7^n-45*6^n+65*5^n-55*4^n+28*3^n-8*2^n+1.
%F G.f.: -3*x*(1680*x^6 -3976*x^5 +3946*x^4 -1807*x^3 +451*x^2 -57*x+3) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)). - _Colin Barker_, Feb 22 2015
%e a(8) = 32857101.
%p f:=n->15*7^n-45*6^n+65*5^n-55*4^n+28*3^n-8*2^n+1;
%o (PARI) Vec(-3*x*(1680*x^6 -3976*x^5 +3946*x^4 -1807*x^3 +451*x^2 -57*x+3) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)) + O(x^100)) \\ _Colin Barker_, Feb 22 2015
%Y Cf. A125630.
%K nonn,base,easy
%O 1,1
%A Aleksandar M. Janjic and _Milan Janjic_, Feb 04 2007
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