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A167487
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a(n) = n*(n + 3)/2 + 8.
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5
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8, 10, 13, 17, 22, 28, 35, 43, 52, 62, 73, 85, 98, 112, 127, 143, 160, 178, 197, 217, 238, 260, 283, 307, 332, 358, 385, 413, 442, 472, 503, 535, 568, 602, 637, 673, 710, 748, 787, 827, 868, 910, 953, 997, 1042, 1088, 1135, 1183, 1232, 1282, 1333, 1385, 1438
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OFFSET
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0,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = n + a(n-1) + 1 with n>1, a(1)=10.
Sum_{n>=0} 1/a(n) = -1/7 + 2*Pi*tanh(sqrt(55)*Pi/2)/sqrt(55). - Amiram Eldar, Dec 13 2022
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MATHEMATICA
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CoefficientList[Series[(8 - 14 x + 7 x^2) / (1 - x)^3, {x, 0, 60}], x] (* Vincenzo Librandi, Sep 16 2013 *)
LinearRecurrence[{3, -3, 1}, {8, 10, 13}, 60] (* Harvey P. Dale, Jul 05 2020 *)
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PROG
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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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