

A146208


a(n)=number of arithmetic progressions of 2 or more integers with product = n.


0



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
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OFFSET

2,1


COMMENTS

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.


LINKS

Table of n, a(n) for n=2..75.


EXAMPLE

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).


CROSSREFS

Sequence in context: A286720 A201393 A327721 * A011227 A155907 A081261
Adjacent sequences: A146205 A146206 A146207 * A146209 A146210 A146211


KEYWORD

easy,nonn


AUTHOR

Naohiro Nomoto, Oct 28 2008


STATUS

approved



