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%I #10 Sep 19 2021 13:04:47
%S 2,2,1,0,0,1,2,0,1,2,2,2,2,0,2,0,1,1,2,0,2,2,0,2,0,0,2,1,2,0,1,1,1,2,
%T 2,2,2,0,2,2,0,2,2,2,2,2,2,2,0,2,0,1,1,1,2,2,2,2,0,2,2,0,2,0,2,0,2,1,
%U 2,2,1,2,2,0,2,1,0,2,1,0,1,2,2,1,2,0,1,2,1,0,2,0,1,2,2,0,1,1,1,1,2,0,1,2,1
%N a(n) = A342926(n) mod 3.
%H Antti Karttunen, <a href="/A347883/b347883.txt">Table of n, a(n) for n = 1..65537</a>
%F a(n) = A342926(n) mod 3.
%t ad[1] = 0; ad[n_] := n * Total@(Last[#]/First[#]& /@ FactorInteger[n]); a[n_] := Mod[ad[DivisorSigma[1, n]] - n, 3]; Array[a, 105] (* _Amiram Eldar_, Sep 18 2021 *)
%o (PARI)
%o A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A342926(n) = (A003415(sigma(n))-n);
%o A347883(n) = (A342926(n)%3);
%Y Cf. A000203, A003415, A342926, A347880 (positions of zeros).
%Y Cf. also A347871.
%K nonn
%O 1,1
%A _Antti Karttunen_, Sep 18 2021
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