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A077972 Expansion of 1/(1+x-x^2+2*x^3). 2
1, -1, 2, -5, 9, -18, 37, -73, 146, -293, 585, -1170, 2341, -4681, 9362, -18725, 37449, -74898, 149797, -299593, 599186, -1198373, 2396745, -4793490, 9586981, -19173961, 38347922, -76695845, 153391689, -306783378, 613566757, -1227133513, 2454267026, -4908534053, 9817068105 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..34.

Index entries for linear recurrences with constant coefficients, signature (-1,1,-2).

FORMULA

a(n) = (-1)^n * A077947(n).

G.f.: Q(0)/2 , where Q(k) = 1 + 1/(1 - x*(4*k+1 - x + 2*x^2 )/( x*(4*k+3 - x + 2*x^2 ) - 1/Q(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Sep 09 2013

PROG

(PARI) Vec(1/(1+x-x^2+2*x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012

CROSSREFS

Sequence in context: A289976 A068036 A077947 * A293354 A293329 A152546

Adjacent sequences:  A077969 A077970 A077971 * A077973 A077974 A077975

KEYWORD

sign,easy

AUTHOR

N. J. A. Sloane, Nov 17 2002

STATUS

approved

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Last modified April 25 13:31 EDT 2019. Contains 322461 sequences. (Running on oeis4.)