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A128951 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 the prime 5 and is not divisible by at least one of the primes 2, 3 and 7. 1
78, 781, 7809, 78096, 780952, 7809524, 78095238, 780952381, 7809523809, 78095238096, 780952380952, 7809523809524, 78095238095238, 780952380952381, 7809523809523809, 78095238095238096, 780952380952380952 (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/5)-floor(10^n/42)+floor(10^n/210)

EXAMPLE

a(6)=780952

MAPLE

f := n->10^n-floor(10^n/5)-floor(10^n/42)+floor(10^n/210);

PROG

(MAGMA) [10^n-Floor(10^n/5)-Floor(10^n/42)+Floor(10^n/210): n in [2..20]]; // Vincenzo Librandi, Oct 02 2011

CROSSREFS

Cf. A092695.

Sequence in context: A129238 A147619 A119093 * A027786 A175383 A190396

Adjacent sequences:  A128948 A128949 A128950 * A128952 A128953 A128954

KEYWORD

nonn

AUTHOR

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

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.