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 A125947 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 2,3,4,5 and at least one of digits 6,7,8,9. 19
 9, 81, 729, 6513, 57369, 495921, 4194969, 34689393, 280607769, 2224214961, 17313344409, 132651929073, 1002605145369, 7490229758001, 55407572177049, 406450276733553, 2960529995462169, 21435301615525041, 154414691892116889, 1107604165960750833 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets Index entries for linear recurrences with constant coefficients, signature (28,-322,1960,-6769,13132,-13068,5040). FORMULA a(n) = 16*7^n-48*6^n+68*5^n-56*4^n+28*3^n-8*2^n+1. G.f.: -3*x*(1680*x^6 -3988*x^5 +3968*x^4 -1819*x^3 +453*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 EXAMPLE a(8) = 34689393. MAPLE f:=n->16*7^n-48*6^n+68*5^n-56*4^n+28*3^n-8*2^n+1; PROG (PARI) Vec(-3*x*(1680*x^6 -3988*x^5 +3968*x^4 -1819*x^3 +453*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 CROSSREFS Cf. A125630. Sequence in context: A267790 A268014 A228972 * A120997 A125630 A100062 Adjacent sequences:  A125944 A125945 A125946 * A125948 A125949 A125950 KEYWORD nonn,base,easy AUTHOR Aleksandar M. Janjic and Milan Janjic, Feb 04 2007 STATUS approved

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Last modified May 21 03:31 EDT 2022. Contains 353887 sequences. (Running on oeis4.)