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A033683
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1 iff n is odd square not divisible by 3.
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3
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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, 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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(A104777(n)) = 1.
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REFERENCES
| J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 105, Eq. (41).
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LINKS
| Index entries for characteristic functions
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FORMULA
| Essentially the series psi_6(z)=(1/2)(theta_2(z/9)-theta_2(z)).
A080995(n) = a(24n+1).
Euler transform of period 144 sequence. - Michael Somos Jan 26 2008
a(n) = A033684(n) * A000035(n).
Dirichlet g.f. zeta(2*s) *(1-2^(-2s)) *(1-3^(-2s)). - R. J. Mathar, Mar 10 2011
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EXAMPLE
| q + q^25 + q^49 + q^121 + q^169 + q^289 + q^361 + q^529 + q^625 + ...
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PROG
| (PARI) {a(n) = if( n%24 == 1, issquare(n), 0)} /* Michael Somos Jan 26 2008 */
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CROSSREFS
| Cf. A098108, A033684.
Sequence in context: A178333 A063524 A084928 * A130638 A030217 A030215
Adjacent sequences: A033680 A033681 A033682 * A033684 A033685 A033686
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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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