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A106600 Number of positive integers <= 10^n that are divisible by no prime exceeding 7. 5
1, 10, 46, 141, 338, 694, 1273, 2155, 3427, 5194, 7575, 10688, 14672, 19674, 25861, 33406, 42487, 53302, 66061, 80988, 98311, 118271, 141124, 167139, 196597, 229785, 267007, 308575, 354820, 406074, 462692, 525030, 593467, 668384, 750177, 839260 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Position of 10^n among the 7-smooth numbers (A002473). Note that all powers of 10 are in A002473. - Zak Seidov, Nov 18 2013

LINKS

Zak Seidov, Table of n, a(n) for n = 0..200

EXAMPLE

A002473(a(2)) = A002473(46)=100.

MATHEMATICA

n = 35; t = Select[ Flatten[ Table[ 7^d*Select[ Flatten[ Table[ 5^c*Select[ Flatten[ Table[2^a*3^b, {a, 0, n*Log[2, 10]}, {b, 0, n*Log[3, 10]}]], # <= 10^n &], {c, 0, n*Log[5, 10]}]], # <= 10^n &], {d, 0, n*Log[5, 10]}]], # <= 10^n &]; Table[ Length[ Select[t, # <= 10^n &]], {n, 0, 35}]

CROSSREFS

Sequence in context: A288117 A213834 A241084 * A085437 A024166 A103501

Adjacent sequences:  A106597 A106598 A106599 * A106601 A106602 A106603

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, May 27 2005

STATUS

approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)