

A260073


Number of triples {x, y, x mod y} of three distinct divisors of n.


5



0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 3, 0, 1, 0, 0, 0, 3, 0, 3, 1, 1, 0, 6, 0, 1, 0, 2, 0, 8, 0, 0, 0, 1, 0, 9, 0, 1, 1, 5, 0, 9, 0, 2, 0, 1, 0, 10, 0, 3, 0, 3, 0, 6, 1, 4, 1, 1, 0, 23, 0, 1, 2, 0, 0, 7, 0, 3, 0, 6, 0, 18, 0, 1
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OFFSET

1,12


COMMENTS

a(n) = 0 if n is a prime power.  Charles R Greathouse IV, Aug 20 2015


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000


EXAMPLE

a(6) = 1 because x = 3, y = 2, x mod y = 1 and 3, 2, 1 are distinct divisors of 6.


PROG

(PARI) a(n)=my(d=divisors(n), x, y, z); sum(i=2, #d2, y=d[i]; sum(j=i+1, #d1, x=d[j]; z=x%y; z && n%z==0)) \\ Charles R Greathouse IV, Aug 20 2015


CROSSREFS

Cf. A027750.
Sequence in context: A111025 A271620 A098018 * A196306 A107093 A051830
Adjacent sequences: A260070 A260071 A260072 * A260074 A260075 A260076


KEYWORD

nonn


AUTHOR

JuriStepan Gerasimov, Aug 19 2015


EXTENSIONS

Corrected and edited by Charles R Greathouse IV, Aug 20 2015


STATUS

approved



