A347883 a(n) = A342926(n) mod 3.

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, 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, 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

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = A342926(n) mod 3.

Mathematica

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 *)

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A342926(n) = (A003415(sigma(n))-n);
A347883(n) = (A342926(n)%3);

Crossrefs

Cf. A000203, A003415, A342926, A347880 (positions of zeros).

Cf. also A347871.

Sequence in context: A370278 A369245 A353310 * A024712 A281497 A198243

Adjacent sequences: A347880 A347881 A347882 * A347884 A347885 A347886

Keyword

nonn

Author

Antti Karttunen, Sep 18 2021

Status

approved