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A106600
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Number of positive integers <= 10^n that are divisible by no prime exceeding 7.
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6
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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
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OFFSET
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0,2
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COMMENTS
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Position of 10^n among the 7-smooth numbers (A002473). Note that all powers of 10 are in A002473. - Zak Seidov, Nov 18 2013
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LINKS
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EXAMPLE
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MATHEMATICA
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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}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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