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A033684
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1 iff n is a square not divisible by 3.
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3
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0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Multiplicative with a(p^e) = 1 if 2 divides e and p != 3, 0 otherwise. Mitch Harris (Harris.Mitchell(AT)mgh.harvard.edu) Jun 09, 2005.
a(n) * A000035(n) = A033683(n).
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REFERENCES
| J. H. Conway and N. J. A. Sloane, Sphere Packings, Lattices and Groups, Springer-Verlag, p. 105, Eq (40).
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LINKS
| Index entries for characteristic functions
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FORMULA
| Essentially the series psi_3(z)=(1/2)(theta_3(z/9)-theta_3(z)).
Dirichlet g.f. zeta(2*s)*(1-3^(-2*s)). - R. J. Mathar, Mar 10 2011
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MAPLE
| A033684 := proc(n)
if issqr(n) then
if n mod 3 = 0 then
0;
else
1;
end if;
else
0;
end if;
end proc:
seq(A033684(n), n=0..80) ; # R. J. Mathar, Oct 07 2011
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CROSSREFS
| Sequence in context: A091444 A091447 A106701 * A080885 A068716 A179828
Adjacent sequences: A033681 A033682 A033683 * A033685 A033686 A033687
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KEYWORD
| nonn,mult
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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