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A126641 a(n) is the number of integers k less than 10^n such that the decimal representation of k lacks the digit 1, at least one of digits 2,3, at least one of digits 4,5, at least one of digits 6,7 and at least one of digits 8,9. 3
9, 73, 537, 3625, 22809, 135913, 777177, 4308265, 23329689, 124104553, 651267417, 3382100905, 17421964569, 89180975593, 454265623257, 2304999893545, 11660373751449, 58845428989033, 296407578308697, 1490778208598185, 7488908074594329, 37584775814704873 (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 (15,-85,225,-274,120).

FORMULA

a(n) = 16*5^n-32*4^n+24*3^n-8*2^n+1.

G.f.: -x*(120*x^4-250*x^3+207*x^2-62*x+9) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)). - Colin Barker, Feb 22 2015

MAPLE

f:=n->16*5^n-32*4^n+24*3^n-8*2^n+1;

PROG

(PARI) Vec(-x*(120*x^4-250*x^3+207*x^2-62*x+9) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)) + O(x^100)) \\ Colin Barker, Feb 22 2015

CROSSREFS

Cf. A125630, A125948, A125947, A125946, A125945, A125940, A125909, A125908, A125880, A125897, A125904, A125858.

Sequence in context: A143571 A244202 A079927 * A081627 A164588 A023001

Adjacent sequences:  A126638 A126639 A126640 * A126642 A126643 A126644

KEYWORD

nonn,base,easy

AUTHOR

Aleksandar M. Janjic and Milan Janjic, Feb 08 2007

STATUS

approved

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Last modified March 28 20:01 EDT 2020. Contains 333103 sequences. (Running on oeis4.)