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A084056 a(n)=-2a(n-1)-a(n-1), a(0)=0, a(1)=1. 3
0, 1, -3, 4, -6, 7, -9, 10, -12, 13, -15, 16, -18, 19, -21, 22, -24, 25, -27, 28, -30, 31, -33, 34, -36, 37, -39, 40, -42, 43, -45, 46, -48, 49, -51, 52, -54, 55, -57, 58, -60, 61, -63, 64, -66, 67, -69, 70, -72, 73, -75, 76, -78, 79, -81, 82, -84, 85, -87, 88, -90 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

abs(a(n))=A032766(n).

FORMULA

a(n)=(1-6n)(-1)^n/4-1/4; G.f.: (x-2*x^2)/((1+x)*(1-x^2)).

CROSSREFS

Sequence in context: A185543 A026322 A049624 * A032766 A189935 A064717

Adjacent sequences:  A084053 A084054 A084055 * A084057 A084058 A084059

KEYWORD

easy,sign

AUTHOR

Paul Barry (pbarry(AT)wit.ie), May 09 2003

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Last modified February 16 17:11 EST 2012. Contains 205938 sequences.