id:A131259 - OEIS Search Results

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a(2n)=A000217(n), a(2n+1)=-2*A000217(n).

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0, 0, 1, -2, 3, -6, 6, -12, 10, -20, 15, -30, 21, -42, 28, -56, 36, -72, 45, -90, 55, -110, 66, -132, 78, -156, 91, -182, 105, -210, 120, -240, 136, -272, 153, -306, 171, -342, 190, -380, 210, -420, 231, -462, 253, -506, 276, -552, 300, -600, 325, -650, 351, -702, 378, -756, 406, -812, 435, -870, 465, -930, 496, -992 (list; graph; listen)

	OFFSET	`0,4`
	MAPLE	`A000217 := proc(n) n(n+1)/2 ; end: A131259 := proc(n) if n mod 2 = 0 then A000217(n/2) ; else -2A000217((n-1)/2) ; fi ; end: seq(A131259(n), n=0..60) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 26 2007`
	CROSSREFS	`Cf, A129819.` `Sequence in context: A039799 A119319 A069808 this_sequence A129648 A129649 A129650` `Adjacent sequences: A131256 A131257 A131258 this_sequence A131260 A131261 A131262`
	KEYWORD	`sign,easy`
	AUTHOR	`Paul Curtz (bpcrtz(AT)free.fr), Sep 28 2007`
	EXTENSIONS	`More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 26 2007`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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