A128957 - OEIS

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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.

86, 857, 8571, 85715, 857142, 8571429, 85714286, 857142857, 8571428571, 85714285715, 857142857142, 8571428571429, 85714285714286, 857142857142857, 8571428571428571, 85714285714285715, 857142857142857142 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,1`
	LINKS	`Vincenzo Librandi, Table of n, a(n) for n = 2..1000` `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);`
	PROG	`(MAGMA) [10^n-Floor(10^n/10)-Floor(10^n/21)+Floor(10^n/210): n in [2..20]]; // Vincenzo Librandi, Oct 02 2011`
	CROSSREFS	`Cf. A092695.` `Sequence in context: A035136 A202524 A202769 * A034277 A206615 A055534` `Adjacent sequences: A128954 A128955 A128956 * A128958 A128959 A128960`
	KEYWORD	`nonn`
	AUTHOR	`Milan R. Janjic (agnus(AT)blic.net), Apr 28 2007`

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Last modified February 14 05:09 EST 2012. Contains 205570 sequences.