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A077984 Expansion of 1/(1+2*x-2*x^2+2*x^3). 0
1, -2, 6, -18, 52, -152, 444, -1296, 3784, -11048, 32256, -94176, 274960, -802784, 2343840, -6843168, 19979584, -58333184, 170311872, -497249280, 1451788672, -4238699648, 12375475200, -36131927040, 105492203776, -307999212032, 899246685696, -2625476203008, 7665444201472 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

FORMULA

a(n) = -2*a(n-1) + 2*a(n-2) - 2*a(n-3).

a(n) is the nearest integer to c*d^n where c=0.7166689603... satisfies 67*c^3-67*c^2+15*c-1=0 and d=-2.9196395658... satisfies d^3+2*d^2-2*d+2=0.

CROSSREFS

Sequence in context: A156989 A077935 A077835 * A052979 A005507 A094864

Adjacent sequences:  A077981 A077982 A077983 * A077985 A077986 A077987

KEYWORD

sign

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Nov 17 2002

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.