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A125945
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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 and at least one of digits 5,6,7,8,9.
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19
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10, 96, 892, 8076, 71500, 619236, 5241652, 43355436, 350740540, 2780210676, 21641505412, 165814383996, 1253254845580, 9362782430916, 69259450905172, 508062802935756, 3700662365318620, 26794126632247956, 193018363703408932, 1384505203965202716
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = 20*7^n-60*6^n+85*5^n-70*4^n+34*3^n-9*2^n+1.
G.f.: -2*x*(2520*x^6 -6054*x^5 +6063*x^4 -2794*x^3 +712*x^2 -92*x +5) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)). - Colin Barker, Feb 23 2015
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MAPLE
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f:=n->20*7^n-60*6^n+85*5^n-70*4^n+34*3^n-9*2^n+1;
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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