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A282718
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Satisfies the tribonacci recurrence: a(n) = a(n-1) + a(n-2) + a(n-3).
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1
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0, 1, 3, 4, 7, 13, 24, 44, 81, 149, 274, 504, 927, 1705, 3136, 5768, 10609, 19513, 35890, 66012, 121415, 223317, 410744, 755476, 1389537, 2555757, 4700770, 8646064, 15902591, 29249425, 53798080, 98950096, 181997601, 334745777, 615693474
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OFFSET
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0,3
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LINKS
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FORMULA
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G.f.: x*(1 + 2*x - x^3 - x^4)/(1 - x - x^2 - x^3). - Bruno Berselli, Mar 03 2017
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MATHEMATICA
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Join[{0, 1, 3}, LinearRecurrence[{1, 1, 1}, {4, 7, 13}, 20]] (* Vincenzo Librandi, Mar 28 2017 *)
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PROG
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(Magma) I:=[0, 1, 3, 4, 7, 13]; [n le 6 select I[n] else Self(n-1)+Self(n-2)+Self(n-3): n in [1..40]]; // Vincenzo Librandi, Mar 28 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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