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Expansion of theta_4(q)^4 - theta_2(q)^4, where theta_2 and theta_4 are the Jacobi theta series.

+0
2

1, -24, 24, -96, 24, -144, 96, -192, 24, -312, 144, -288, 96, -336, 192, -576, 24, -432, 312, -480, 144, -768, 288, -576, 96, -744, 336, -960, 192, -720, 576, -768, 24, -1152, 432, -1152, 312, -912, 480, -1344, 144, -1008, 768, -1056, 288, -1872 (list; graph; listen)

	OFFSET	`0,2`
	LINKS	`C. Pache, Shells of selfdual lattices viewed as spherical designs` `Eric Weisstein's World of Mathematics, Eisenstein Series`
	FORMULA	`G.f.: theta_4(q)^4 - theta_2(q)^4.`
	PROGRAM	`(PARI) a(n)=if(n<1, n==0, (-1)^n24sumdiv(n, d, d%2*d))`
	CROSSREFS	`Sequence in context: A040553 A022358 A122505 this_sequence A004011 A056465 A056455` `Adjacent sequences: A103637 A103638 A103639 this_sequence A103641 A103642 A103643`
	KEYWORD	`sign`
	AUTHOR	`Ralf Stephan (ralf(AT)ark.in-berlin.de), Feb 18 2005`

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

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