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A161705
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a(n) = 18*n + 1.
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19
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1, 19, 37, 55, 73, 91, 109, 127, 145, 163, 181, 199, 217, 235, 253, 271, 289, 307, 325, 343, 361, 379, 397, 415, 433, 451, 469, 487, 505, 523, 541, 559, 577, 595, 613, 631, 649, 667, 685, 703, 721, 739, 757, 775, 793, 811, 829, 847, 865, 883, 901, 919, 937, 955
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OFFSET
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0,2
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COMMENTS
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These numbers can be written as the sum of four integer cubes as a(n) = (2*n + 14)^3 + (3*n + 30)^3 + (- 2*n - 23)^3 + (- 3*n - 26)^3. - Arkadiusz Wesolowski, Aug 15 2013
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LINKS
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FORMULA
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a(n) = 18*n + 1, n >= 0.
G.f.: (1 + 17*x)/(1-x)^2.
E.g.f.: (1 + 18*x)*exp(x).
a(n) = 2*a(n-1) - a(n-2). (End)
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MAPLE
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MATHEMATICA
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LinearRecurrence[{2, -1}, {1, 19}, 60] (* G. C. Greubel, Feb 17 2017 *)
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PROG
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CROSSREFS
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Cf. A005408, A016813, A016921, A017281, A017533, A128470, A158057, A161700, A161709, A161714, A287326 (fourth column).
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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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