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A126633 a(n) is the number of nonnegative integers k less than 10^n such that the decimal representation of k lacks at least one of digits 1, 2, at least one of digits 3,4, at least one of digits 5,6 and at least one of digits 7,8,9. 3

%I #20 Apr 07 2024 17:43:10

%S 10,94,832,6946,54880,412714,2975752,20722306,140285200,928323034,

%T 6031661272,38617025266,244322679520,1531014308554,9519483716392,

%U 58816232361826,361524350929840,2212804949145274,13497228660885112

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

%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_06">Index entries for linear recurrences with constant coefficients</a>, signature (21,-175,735,-1624,1764,-720).

%F a(n) = 24*6^n-60*5^n+62*4^n-33*3^n+9*2^n-1.

%F G.f.: -2*x*(360*x^5-882*x^4+713*x^3-304*x^2+58*x-5) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)). - _Colin Barker_, May 04 2014

%p A126633:=n->24*6^n-60*5^n+62*4^n-33*3^n+9*2^n-1; seq(A126633(n), n=1..20);

%t Table[24*6^n - 60*5^n + 62*4^n - 33*3^n + 9*2^n - 1, {n, 20}] (* _Wesley Ivan Hurt_, May 03 2014 *)

%t LinearRecurrence[{21,-175,735,-1624,1764,-720},{10,94,832,6946,54880,412714},30] (* _Harvey P. Dale_, May 05 2018 *)

%Y Cf. A125630, A125948, A125947, A125946, A125945, A125910, A125909, A125908, A125880, A125897, A125904, A125858.

%K nonn,base,easy,changed

%O 1,1

%A Aleksandar M. Janjic and _Milan Janjic_, Feb 08 2007

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Last modified April 18 03:33 EDT 2024. Contains 371767 sequences. (Running on oeis4.)