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A347883 a(n) = A342926(n) mod 3. 5
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 (list; graph; refs; listen; history; text; internal format)
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: A210502 A283988 A276204 * A024712 A281497 A198243

Adjacent sequences:  A347880 A347881 A347882 * A347884 A347885 A347886

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 18 2021

STATUS

approved

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Last modified November 29 18:41 EST 2021. Contains 349416 sequences. (Running on oeis4.)