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A260073 Number of triples {x, y, x mod y} of three distinct divisors of n. 5

%I #36 Sep 05 2015 04:44:41

%S 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,

%T 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,

%U 3,0,6,0,18,0,1

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

%C a(n) = 0 if n is a prime power. - _Charles R Greathouse IV_, Aug 20 2015

%H Charles R Greathouse IV, <a href="/A260073/b260073.txt">Table of n, a(n) for n = 1..10000</a>

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

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

%Y Cf. A027750.

%K nonn

%O 1,12

%A _Juri-Stepan Gerasimov_, Aug 19 2015

%E Corrected and edited by _Charles R Greathouse IV_, Aug 20 2015

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Last modified August 28 15:13 EDT 2024. Contains 375507 sequences. (Running on oeis4.)