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A071523
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Number of 11-smooth numbers <= n.
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0
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12, 13, 14, 15, 15, 16, 16, 17, 18, 19, 19, 20, 21, 21, 22, 23, 23, 24, 24, 25, 26, 26, 27, 28, 28, 28, 28, 29, 29, 30, 30, 31, 32, 32, 32, 33, 34, 35, 35, 35, 35, 36, 37, 38, 38, 38, 38, 39, 39, 39, 40, 41, 41, 42, 42, 42, 42, 43, 43, 44
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| An 11-smooth number is a number of the form 2^x*3^y*5^z*7^u*11^v (x,y,z,u,v) >= 0.
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FORMULA
| a(n) = Card{ k | A051038(k) <= n }
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PROG
| (PARI) a(n)=sum(k=1, n, (k<4)|13>vecmax(factor(k)~[1, ]))
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CROSSREFS
| Sequence in context: A087999 A106614 A043272 * A070696 A053834 A043273
Adjacent sequences: A071520 A071521 A071522 * A071524 A071525 A071526
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KEYWORD
| easy,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 02 2002
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