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A086669 a(n) = number of divisors of n that are fundamental discriminants.

%I A086669 #8 Aug 23 2017 09:49:10
%S A086669 1,1,1,1,2,1,1,2,1,2,1,2,2,1,2,2,2,1,1,2,2,1,1,4,2,2,1,2,2,2,1,2,2,2,
%T A086669 2,2,2,1,2,4,2,2,1,2,2,1,1,4,1,2,2,2,2,1,2,4,2,2,1,4,2,1,2,2,4,2,1,2,
%U A086669 2,2,1,4,2,2,2,2,2,2,1,4,1,2,1,4,4,1,2,4,2,2,2,2,2,1,2,4,2,1,2,2
%N A086669 a(n) = number of divisors of n that are fundamental discriminants.
%H A086669 Antti Karttunen, <a href="/A086669/b086669.txt">Table of n, a(n) for n = 1..16385</a>
%F A086669 a(n) = Sum_{d|n} A290098(d).
%e A086669 10 has divisors 1, 2, 5 and 10 of which 1 and 5 are fundamental discriminants, so a(10)=2
%o A086669 (PARI) for (n=1,100,s=0; fordiv(i=n,i,s+=isfundamental(i)); print1(","s))
%o A086669 (PARI) A086669(n) = sumdiv(n, i, isfundamental(i)); \\ _Antti Karttunen_, Aug 22 2017
%Y A086669 Cf. A003658, A290098.
%K A086669 nonn
%O A086669 1,5
%A A086669 _Jon Perry_, Jul 27 2003