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A027084
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G.f.: x^2*(x^2 + x + 1)/(x^4 - 2*x + 1).
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7
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1, 3, 7, 14, 27, 51, 95, 176, 325, 599, 1103, 2030, 3735, 6871, 12639, 23248, 42761, 78651, 144663, 266078, 489395, 900139, 1655615, 3045152, 5600909, 10301679, 18947743, 34850334, 64099759, 117897839, 216847935, 398845536
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OFFSET
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2,2
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COMMENTS
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Lengths of palindromic prefixes of the ternary tribonacci word A080843 [A. Glen]. - N. J. A. Sloane, Jun 09 2019
Original definition was: a(n) = (1/2)*T(n,n+2), T given by A027082.
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LINKS
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FORMULA
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Positive numbers of the form (t_n + t_{n+2} - 3)/2, n>1, where {t_n} are the tribonacci numbers A000073 [A. Glen]. See Mousavi-Shallit, 2014. - N. J. A. Sloane, Jun 09 2019
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PROG
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(PARI) Vec(x^2*(x^2 + x + 1)/(x^4 - 2*x + 1) + O(x^50)) \\ Michel Marcus, Dec 29 2014
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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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EXTENSIONS
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STATUS
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approved
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