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%I #9 Nov 20 2023 11:53:22
%S 1,1,0,1,0,0,0,1,1,0,2,0,2,0,0,1,2,1,1,0,0,2,0,0,1,2,0,0,2,0,2,1,0,2,
%T 0,1,2,1,0,0,0,0,2,2,0,0,0,0,1,1,0,2,2,0,0,0,0,2,0,0,0,2,0,1,0,0,0,2,
%U 0,0,2,1,2,2,0,1,0,0,2,0,1
%N Coefficients in expansion of Dirichlet series Product_p (1-(Kronecker(m,p)+1)*p^(-s)+Kronecker(m,p)*p^(-2s))^(-1) for m = 38.
%H Amiram Eldar, <a href="/A035220/b035220.txt">Table of n, a(n) for n = 1..10000</a>
%F From _Amiram Eldar_, Nov 20 2023: (Start)
%F a(n) = Sum_{d|n} Kronecker(38, d).
%F Multiplicative with a(p^e) = 1 if Kronecker(38, p) = 0 (p = 2 or 19), a(p^e) = (1+(-1)^e)/2 if Kronecker(38, p) = -1 (p is in A038916), and a(p^e) = e+1 if Kronecker(38, p) = 1 (p is in A038915 \ {2, 19}).
%F Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = log(6*sqrt(38)+37)/sqrt(38) = 0.698181923868... . (End)
%t a[n_] := DivisorSum[n, KroneckerSymbol[38, #] &]; Array[a, 100] (* _Amiram Eldar_, Nov 20 2023 *)
%o (PARI) my(m = 38); direuler(p=2,101,1/(1-(kronecker(m,p)*(X-X^2))-X))
%o (PARI) a(n) = sumdiv(n, d, kronecker(38, d)); \\ _Amiram Eldar_, Nov 20 2023
%Y Cf. A038915, A038916.
%K nonn,easy,mult
%O 1,11
%A _N. J. A. Sloane_
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