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%I #17 May 04 2018 17:11:20
%S 0,0,0,2,0,1,0,2,3,1,0,1,0,1,1,2,0,1,0,1,1,1,0,1,5,1,3,1,0,1,0,2,1,1,
%T 1,1,0,1,1,1,0,1,0,1,1,1,0,1,7,1,1,1,0,1,1,1,1,1,0,1,0,1,1,2,1,1,0,1,
%U 1,1,0,1,0,1,1,1,1,1,0,1,3,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,1
%N Greatest common divisor of the proper divisors of n, 0 if there are none.
%C Here a proper divisor d of n is a divisor of n such that 1 < d < n.
%H Antti Karttunen, <a href="/A182936/b182936.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = 0 if n is not composite, p if n is a proper power of prime p, and 1 otherwise. - _Franklin T. Adams-Watters_, Mar 22 2011
%p A182936 := n -> igcd(op(numtheory[divisors](n) minus {1,n}));
%p seq(A182936(i), i=1..79); # _Peter Luschny_, Mar 22 2011
%t Join[{0},Table[GCD@@Most[Rest[Divisors[n]]],{n,2,110}]] (* _Harvey P. Dale_, May 04 2018 *)
%o (PARI) A182936(n) = { my(divs=divisors(n)); if(#divs<3,0,gcd(vector(numdiv(n)-2,k,divs[k+1]))); }; \\ _Antti Karttunen_, Sep 23 2017
%Y Cf. A048671.
%K nonn
%O 1,4
%A _Peter Luschny_, Mar 22 2011
%E More terms from _Antti Karttunen_, Sep 23 2017
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