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A037213 Expansion of sum(n*q^(n^2), n=0..inf). 6
0, 1, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; internal format)
OFFSET

0,5

COMMENTS

Multiplicative with a(p^(2e)) = p^e, a(p^(2e+1)) = 0. Mitch Harris (Harris.Mitchell(AT)mgh.harvard.edu) Jun 09, 2005.

a(n) is the square root of n if n is square, zero otherwise [From Carl R. White (oeisfan(AT)phodd.net), May 23 2009]

FORMULA

Dirichlet generating function: zeta(2s-1). - Franklin T. Adams-Watters, Sep 11 2005.

a(n) = sqrt(n) * floor( cos^2(pi * sqrt(n)) ) [From Carl R. White (oeisfan(AT)phodd.net), May 23 2009]

a(n) = A000196(n)*A010052(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 27 2010]

CROSSREFS

Sequence in context: A174469 A112166 A112167 * A092197 A083804 A028597

Adjacent sequences:  A037210 A037211 A037212 * A037214 A037215 A037216

KEYWORD

nonn,mult

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 17 23:08 EST 2012. Contains 206085 sequences.