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A156810
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a(n) = 225*n^2 - 251*n + 70.
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1
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70, 44, 468, 1342, 2666, 4440, 6664, 9338, 12462, 16036, 20060, 24534, 29458, 34832, 40656, 46930, 53654, 60828, 68452, 76526, 85050, 94024, 103448, 113322, 123646, 134420, 145644, 157318, 169442, 182016, 195040, 208514, 222438, 236812, 251636
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OFFSET
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0,1
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LINKS
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FORMULA
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900*a(n) + 1 = (450*n - 251)^2.
G.f.: (70 - 166*x + 546*x^2)/(1-x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). (End)
E.g.f.: (70 - 26*x + 225*x^2)*exp(x). - G. C. Greubel, Jun 10 2021
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MATHEMATICA
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PROG
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(Magma) I:=[70, 44, 468]; [n le 3 select I[n] else 3*Self(n-1) -3*Self(n-2) +Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 08 2012
(Sage) [225*n^2 - 251*n + 70 for n in (0..40)] # G. C. Greubel, Jun 10 2021
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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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