id:A140756 - OEIS Search Results

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Count up to k sequence with alternating signs (k always positive).

+0
2

1, -1, 2, 1, -2, 3, -1, 2, -3, 4, 1, -2, 3, -4, 5, -1, 2, -3, 4, -5, 6, 1, -2, 3, -4, 5, -6, 7, -1, 2, -3, 4, -5, 6, -7, 8, 1, -2, 3, -4, 5, -6, 7, -8, 9, -1, 2, -3, 4, -5, 6, -7, 8, -9, 10, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -1, 2, -3, 4, -5, 6, -7, 8, -9, 10, -11, 12, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -12, 13 (list; table; graph; listen)

	OFFSET	`1,3`
	FORMULA	`G.f.: A(x) = x(1+3x^2+2x^4)/((1-x)(1-x^2)^2).` `Regarded as a triangle, T(n,k) = (-1)^{n-k} * k.`
	CROSSREFS	`Cf. A002260, A140757.` `Sequence in context: A138060 A023121 A136261 this_sequence A002260 A133994 A066041` `Adjacent sequences: A140753 A140754 A140755 this_sequence A140757 A140758 A140759`
	KEYWORD	`easy,sign,tabl`
	AUTHOR	`Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), May 27 2008`

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

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