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A128957 a(n) is equal to the number of positive integers m less than or equal to 10^n such that m is not divisible by at least one of the primes 2,5 and is not divible by at least one of the primes 3,7. +0
1
86, 857, 8571, 85715, 857142, 8571429, 85714286, 857142857, 8571428571, 85714285715, 857142857142, 8571428571429, 85714285714286, 857142857142857, 8571428571428571, 85714285714285715, 857142857142857142 (list; graph; listen)
OFFSET

2,1

LINKS

Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets

FORMULA

f(n)= 10^n-floor(10^n/10)-floor(10^n/21)+floor(10^n/210)

EXAMPLE

a(6)=857142

MAPLE

f := n->10^n-floor(10^n/10)-floor(10^n/21)+floor(10^n/210);

CROSSREFS

Cf. A092695.

Sequence in context: A113690 A043379 A035136 this_sequence A034277 A055534 A017802

Adjacent sequences: A128954 A128955 A128956 this_sequence A128958 A128959 A128960

KEYWORD

nonn

AUTHOR

Milan R. Janjic (agnus(AT)blic.net), Apr 28 2007

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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