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A010021
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a(0) = 1, a(n) = 32*n^2 + 2 for n > 0.
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5
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1, 34, 130, 290, 514, 802, 1154, 1570, 2050, 2594, 3202, 3874, 4610, 5410, 6274, 7202, 8194, 9250, 10370, 11554, 12802, 14114, 15490, 16930, 18434, 20002, 21634, 23330, 25090, 26914, 28802, 30754, 32770, 34850, 36994, 39202, 41474, 43810, 46210, 48674, 51202
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OFFSET
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0,2
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COMMENTS
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Sequence found by reading the line segment from 1 to 34 together with the line from 34, in the direction 34, 130, ..., in the rectangular spiral whose vertices are the generalized 18-gonal numbers A274979.
The spiral begins as follows:
46_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _18
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| 0 |
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| 1 15
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51
(End)
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LINKS
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FORMULA
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MATHEMATICA
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CoefficientList[Series[(1 + x) (1 + 30 x + x^2)/(1 - x)^3, {x, 0, 40}], x] (* Vincenzo Librandi, Jun 25 2014 *)
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CROSSREFS
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Cf. A274979 (generalized 18-gonal numbers).
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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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