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Search: id:A146208
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| A146208 |
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a(n)=number of arithmetic progressions of 2 or more integers with product = n. |
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+0
1
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| 4, 6, 6, 4, 10, 4, 11, 8, 10, 4, 12, 4, 8, 12, 12, 4, 12, 4, 12, 10, 8, 4, 26, 6, 8, 9, 14, 4, 16, 4, 13, 8, 8, 10, 20, 4, 8, 8, 20, 4, 18, 4, 12, 16, 8, 4, 26, 6, 12, 8, 12, 4, 16, 10, 16, 8, 8, 4, 26, 4, 8, 14, 19, 8, 18, 4, 12, 8, 16, 4, 24, 4, 8, 12
(list; graph; listen)
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OFFSET
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2,1
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COMMENT
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a(n)=number of all integer triples (x,y,z) such that Product_{k=0..z} (x + (y*k)) = n, where n>1, z>0.
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EXAMPLE
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a(9)=8 as we can have (x=-3,y=0,z=1; -3*-3), (x=3,y=0,z=1; 3*3), (x=-9,y=8,z=1; -9*-1), (x=1,y=8,z=1; 1*9), (x=-1,y=-8,z=1; -1*-9), (x=9,y=-8,z=1; 9*1), (x=3,y=-2,z=3; 3*1*-1*-3), (x=-3,y=2,z=3; -3*-1*1*3).
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CROSSREFS
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Sequence in context: A021686 A019923 A019800 this_sequence A011227 A155907 A081261
Adjacent sequences: A146205 A146206 A146207 this_sequence A146209 A146210 A146211
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KEYWORD
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easy,nonn
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AUTHOR
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Naohiro Nomoto (fwqfg726(AT)ybb.ne.jp), Oct 28 2008
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