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 A049863 a(n)=Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; 3 initial terms required. 1
 0, 3, 4, 7, 11, 21, 39, 74, 138, 258, 481, 898, 1676, 3129, 5841, 10904, 20355, 37998, 70933, 132415, 247187, 461439, 861396, 1608020, 3001788, 5603619, 10460614, 19527460, 36453089, 68049183, 127031520, 237137411, 442678728 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Index entries for linear recurrences with constant coefficients, signature (2, 0, -1, 1). FORMULA a(n)=2*a(n-1)-a(n-3)+a(n-4); 4 initial terms required. G.f.: (x^3+2x^2-3x)/(x^4-x^3+2x-1) [From Harvey P. Dale, Apr 26 2011] MATHEMATICA LinearRecurrence[{2, 0, -1, 1}, {0, 3, 4, 7}, 40] (* or *) CoefficientList[ Series[(x^3+2x^2-3x)/(x^4-x^3+2x-1), {x, 0, 50}], x] (* Harvey P. Dale, Apr 26 2011 *) CROSSREFS Sequence in context: A042593 A041018 A072255 * A025068 A049928 A002364 Adjacent sequences:  A049860 A049861 A049862 * A049864 A049865 A049866 KEYWORD nonn AUTHOR STATUS approved

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Last modified May 21 00:36 EDT 2022. Contains 353886 sequences. (Running on oeis4.)