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A074943
a(n) = tau(n) mod 3.
2
1, 2, 2, 0, 2, 1, 2, 1, 0, 1, 2, 0, 2, 1, 1, 2, 2, 0, 2, 0, 1, 1, 2, 2, 0, 1, 1, 0, 2, 2, 2, 0, 1, 1, 1, 0, 2, 1, 1, 2, 2, 2, 2, 0, 0, 1, 2, 1, 0, 0, 1, 0, 2, 2, 1, 2, 1, 1, 2, 0, 2, 1, 0, 1, 1, 2, 2, 0, 1, 2, 2, 0, 2, 1, 0, 0, 1, 2, 2, 1, 2, 1, 2, 0, 1, 1, 1, 2, 2, 0, 1, 0, 1, 1, 1, 0, 2, 0, 0, 0, 2, 2, 2, 2, 2
OFFSET
1,2
FORMULA
From Amiram Eldar, Apr 16 2024: (Start)
a(n) = A010872(A000005(n)).
a(A059269(n)) = 0; a(A211337(n)) = 1; a(A211338(n)) = 2.
Conjecture: Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 9*zeta(3)/Pi^2 = 1.0961... . The conjecture is true if A211337 and A211338 have the same asymptotic density (see also A059269). (End)
MATHEMATICA
Mod[DivisorSigma[0, Range[110]], 3] (* Harvey P. Dale, Dec 22 2013 *)
PROG
(PARI) a(n)=numdiv(n)%3
(Scheme) (define (A074943 n) (modulo (A000005 n) 3)) ;; Antti Karttunen, Jul 26 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Oct 04 2002
STATUS
approved