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A359302
Dirichlet g.f.: zeta(s)^2/zeta(3*s-2).
1
1, 2, 2, 3, 2, 4, 2, 0, 3, 4, 2, 6, 2, 4, 4, -3, 2, 6, 2, 6, 4, 4, 2, 0, 3, 4, -5, 6, 2, 8, 2, -6, 4, 4, 4, 9, 2, 4, 4, 0, 2, 8, 2, 6, 6, 4, 2, -6, 3, 6, 4, 6, 2, -10, 4, 0, 4, 4, 2, 12, 2, 4, 6, -9, 4, 8, 2, 6, 4, 8, 2, 0, 2, 4, 6, 6, 4, 8, 2, -6, -13, 4, 2, 12
OFFSET
1,2
LINKS
FORMULA
Sum_{k=1..n} a(k) ~ 3*n.
Multiplicative with a(p) = 2, and a(p^e) = 3 - (e-2)*(p^2-1) for e >= 2. - Amiram Eldar, Sep 15 2023
MATHEMATICA
f[p_, e_] := 3 - (e-2)*(p^2-1); f[p_, 1] = 2; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Sep 15 2023 *)
PROG
(PARI) for(n=1, 100, print1(direuler(p=2, n, (1 - p^2*X^3)/(1-X)^2)[n], ", "))
CROSSREFS
Cf. A344326.
Sequence in context: A274517 A355583 A368543 * A366147 A367170 A369306
KEYWORD
sign,easy,mult
AUTHOR
Vaclav Kotesovec, Dec 25 2022
STATUS
approved