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A125948
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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 1,2,3, at least one of digits 4,5,6 and at least one of digits 7,8,9.
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19
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10, 100, 982, 9388, 86950, 778780, 6748822, 56713708, 463661830, 3700940860, 28941318262, 222422713228, 1684544507110, 12602134130140, 93308618633302, 684912371803948, 4990975002030790, 36147245625290620, 260449744313893942
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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) = 27*7^n-81*6^n+108*5^n-81*4^n+36*3^n-9*2^n+1.
G.f.: -2*x*(2520*x^6 -6012*x^5 +5990*x^4 -2754*x^3 +701*x^2 -90*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->27*7^n-81*6^n+108*5^n-81*4^n+36*3^n-9*2^n+1;
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PROG
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(PARI) vector(100, n, 27*7^n-81*6^n+108*5^n-81*4^n+36*3^n-9*2^n+1) \\ Colin Barker, Feb 23 2015
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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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