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 A265107 Expansion of (2*x^4+x^3+x)/(-x^2-2*x+1). 5
 0, 1, 2, 6, 16, 38, 92, 222, 536, 1294, 3124, 7542, 18208, 43958, 106124, 256206, 618536, 1493278, 3605092, 8703462, 21012016, 50727494, 122467004, 295661502, 713790008, 1723241518, 4160273044, 10043787606, 24247848256, 58539484118, 141326816492, 341193117102 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Colin Barker, Table of n, a(n) for n = 0..1000 M. Diepenbroek, M. Maus, A. Stoll, Pattern Avoidance in Reverse Double Lists, Preprint 2015. See Table 3. Index entries for linear recurrences with constant coefficients, signature (2,1). FORMULA From Colin Barker, Apr 12 2016: (Start) a(n) = ((1+sqrt(2))^n*(-5+4*sqrt(2)) + (1-sqrt(2))^n*(5+4*sqrt(2)))/sqrt(2) for n>2. a(n) = 2*a(n-1)+a(n-2) for n>4. (End) PROG (PARI) concat(0, Vec(x*(1+x)*(1-x+2*x^2)/(1-2*x-x^2) + O(x^50))) \\ Colin Barker, Apr 12 2016 CROSSREFS Cf. A002605, A265106, A265278, A270810. Sequence in context: A093041 A156616 A265758 * A217631 A046209 A285885 Adjacent sequences:  A265104 A265105 A265106 * A265108 A265109 A265110 KEYWORD nonn,easy AUTHOR Alois P. Heinz, Apr 06 2016 STATUS approved

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Last modified October 20 22:05 EDT 2019. Contains 328291 sequences. (Running on oeis4.)