A101677 - OEIS

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A101677

a(n)=a(n-1)-2a(n-2)+2a(n-3)-2a(n-4)+2a(n-5)-a(n-6).

1, 1, -1, -2, -2, -2, -1, -1, -3, -4, -4, -4, -3, -3, -5, -6, -6, -6, -5, -5, -7, -8, -8, -8, -7, -7, -9, -10, -10, -10, -9, -9, -11, -12, -12, -12, -11, -11, -13, -14, -14, -14, -13, -13, -15, -16, -16, -16, -15, -15, -17, -18, -18, -18, -17, -17, -19, -20, -20, -20, -19, -19, -21, -22, -22, -22, -21, -21, -23, -24, -24, -24, -23, -23, -25, -26, -26, -26, -25, -25, -27 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,4`
	COMMENTS	`Partial sums of A101676, second partial sums of A101675. a(3(n+1))=-A014681(n+1);a(3n)=a(3n+1)=0^n-A014681(n);a(3n+2)=-(n+1).`
	FORMULA	`G.f.: (1-x-x^2)/((1-x)^2(1+x^2+x^4)); a(n)=2sqrt(3)sin(2pin/3)/9+cos(pin/3)+sin(pi*n/3)/sqrt(3)-n/3.`
	CROSSREFS	`Sequence in context: A118400 A159853 A087698 * A152067 A193884 A128084` `Adjacent sequences: A101674 A101675 A101676 * A101678 A101679 A101680`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Dec 11 2004`

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Last modified February 15 19:15 EST 2012. Contains 205852 sequences.