id:A122876 - OEIS Search Results

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a(0)=1, a(1)=1, a(2)=2, a(n)=a(n-1)-a(n-2) for n>2.

+0
2

1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1, 1, 2, 1, -1, -2, -1 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`Essentially the same as A057079, A087204 and A100051.`
	FORMULA	`a(n)=Sum_{k, 0<=k<=[n/2]}(-2)^kA055830(n-k,k) . G.f.:(1+2x^2)/(1-x+x^2)` `a(n)=(1/2)[(1/2)-(1/2)Isqrt(3)]^(n-1)+(1/2)[(1/2)+(1/2)Isqrt(3)]^(n-1)+(1/2)I[(1/2)-(1/2)I sqrt(3)]^(n-1)sqrt(3)-(1/2)I[(1/2)+(1/2)Isqrt(3)]^(n-1)sqrt(3)+[C(2*n,n) mod 2], with n>=0 and I=sqrt(-1) [From Paolo P. Lava (ppl(AT)spl.at), Nov 19 2008]`
	CROSSREFS	`Sequence in context: A016010 A099837 A100051 this_sequence A100063 A132419 A131556` `Adjacent sequences: A122873 A122874 A122875 this_sequence A122877 A122878 A122879`
	KEYWORD	`sign`
	AUTHOR	`Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 24 2006`

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

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