A155041 - OEIS

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A155041

Diagonal sums of symmetric (1,-1)-triangle A155040.

1, 1, 2, 0, 1, -1, 2, 0, 3, -1, 2, -2, 3, -1, 4, -2, 3, -3, 4, -2, 5, -3, 4, -4, 5, -3, 6, -4, 5, -5, 6, -4, 7, -5, 6, -6, 7, -5, 8, -6, 7, -7, 8, -6, 9, -7, 8, -8, 9, -7, 10, -8, 9, -9, 10, -8, 11, -9, 10, -10, 11, -9, 12, -10, 11, -11, 12, -10, 13, -11, 12, -12, 13, -11, 14, -12, 13 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`First differences of A155041 are (-1)^n*A008611.`
	FORMULA	`G.f.: (1+x+x^2)/(1-x^2+x^3-x^5);` `a(2n)=A008611(n+2)=[x^n](1+x-x^2)/(1-x-x^3+x^4); a(2n+1)=[x^n](1-x-x^2)/(1-x-x^3+x^4).`
	CROSSREFS	`Sequence in context: A185279 A088432 A071466 * A108455 A193759 A117468` `Adjacent sequences: A155038 A155039 A155040 * A155042 A155043 A155044`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jan 19 2009`

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Last modified February 16 05:39 EST 2012. Contains 205860 sequences.