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 A109247 Expansion of (1-3x^2-3x^3+x^4)/(1+x^4). 4
 1, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3, 0, 0, 3, 3, 0, 0, -3, -3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Row sums of Riordan array (1-x-2x^2,x(1-x)), A109246. After the initial terms, cyclic with period 8: [0,0,-3,-3,0,0,3,3]. - Antti Karttunen, Aug 12 2017 LINKS Antti Karttunen, Table of n, a(n) for n = 0..8191 Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, -1). FORMULA a(0)=1, a(1)=0, a(2)=-3, a(3)=-3, a(4)=0, a(n)=-a(n-4) - Harvey P. Dale, Mar 24 2012 For n > 0, a(n) = -3 * A132380(n). - Antti Karttunen, Aug 12 2017 MATHEMATICA CoefficientList[Series[(1-3x^2-3x^3+x^4)/(1+x^4), {x, 0, 90}], x] (* or *) Join[{1}, LinearRecurrence[{0, 0, 0, -1}, {0, -3, -3, 0}, 90]] (* Harvey P. Dale, Mar 24 2012 *) PROG (Scheme) (define (A109247 n) (case n ((0) 1) ((1 4) 0) ((2 3) -3) (else (- (A109247 (- n 4)))))) ;; (After Harvey P. Dale's Mar 24 2012 recurrence) - Antti Karttunen, Aug 12 2017 CROSSREFS Cf. A132380. Sequence in context: A257094 A256004 A269707 * A021307 A170852 A245320 Adjacent sequences:  A109244 A109245 A109246 * A109248 A109249 A109250 KEYWORD easy,sign AUTHOR Paul Barry, Jun 23 2005 STATUS approved

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Last modified January 25 03:49 EST 2020. Contains 331241 sequences. (Running on oeis4.)