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%I #19 Oct 30 2022 05:27:57
%S 1,2,2,2,2,4,2,0,2,4,2,0,2,4,4,0,2,0,2,0,4,4,2,0,2,4,0,0,2,0,2,0,4,4,
%T 4,0,2,4,4,0,2,0,2,0,0,4,2,0,2,0,4,0,2,0,4,0,4,4,2,0,2,4,0,0,4,0,2,0,
%U 4,0,2,0,2,4,0,0,4,0,2,0,0,4,2,0,4,4,4,0,2,0,4,0,4,4,4,0,2,0,0,0,2,0,2,0,0
%N Number of permutations of the positive divisors of n, where every element is coprime to its adjacent elements.
%C Depends only on prime signature. - _Reinhard Zumkeller_, May 24 2010
%H Reinhard Zumkeller, <a href="/A109810/b109810.txt">Table of n, a(n) for n = 1..10000</a>
%F a(1)=1, a(p) = 2, a(p^2) = 2, a(p*q) = 4 (where p and q are distinct primes), all other terms are 0.
%F a(A033942(n))=0; a(A037143(n))>0; a(A000430(n))=2; a(A006881(n))=4. - _Reinhard Zumkeller_, May 24 2010
%e The divisors of 6 are 1, 2, 3 and 6. Of the permutations of these integers, only (6,1,2,3), (6,1,3,2), (2,3,1,6) and (3,2,1,6) are such that every pair of adjacent elements is coprime.
%Y Cf. A178254. - _Reinhard Zumkeller_, May 24 2010
%K nonn
%O 1,2
%A _Leroy Quet_, Aug 16 2005
%E Terms 17 to 59 from _Diana L. Mecum_, Jul 18 2008
%E More terms from _David Wasserman_, Oct 01 2008
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