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A125946
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 3,4,5 and at least one of digits 6,7,8,9.
18
10, 98, 940, 8798, 80140, 709238, 6096100, 50950718, 415060060, 3305238278, 25807024660, 198131841038, 1499550640780, 11213044626518, 82997777543620, 609099122145758, 4437879770746300, 32138240678881958, 231547934781860980, 1661033550903240878
OFFSET
1,1
FORMULA
a(n) = 24*7^n-72*6^n+98*5^n-76*4^n+35*3^n-9*2^n+1.
G.f.: -2*x*(2520*x^6 -6042*x^5 +6043*x^4 -2783*x^3 +708*x^2 -91*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
MAPLE
f:=n->24*7^n-72*6^n+98*5^n-76*4^n+35*3^n-9*2^n+1;
PROG
(PARI) vector(100, n, 24*7^n-72*6^n+98*5^n-76*4^n+35*3^n-9*2^n+1) \\ Colin Barker, Feb 23 2015
CROSSREFS
Cf. A125630.
Sequence in context: A363186 A264462 A198968 * A158513 A125880 A125445
KEYWORD
nonn,base,easy
AUTHOR
Aleksandar M. Janjic and Milan Janjic, Feb 04 2007
STATUS
approved