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A072749 Counting factor 5 in square-free numbers <=n. +0
5
0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14 (list; graph; listen)
OFFSET

1,7

EXAMPLE

The first 10 square-free numbers are: 1, 2, 3, 5, 6=2*3, 7, 10=2*5, 11, 13, and 14=2*7

5 and 10 are divisible by 5, therefore a(10)=2.

CROSSREFS

Cf. A005117, A072747, A072748, A072750, A072751.

Sequence in context: A074280 A000523 A124156 this_sequence A066490 A124230 A090973

Adjacent sequences: A072746 A072747 A072748 this_sequence A072750 A072751 A072752

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Jul 08 2002

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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