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A131895
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a(n) = (n + 2)*(5*n + 1)/2.
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2
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1, 9, 22, 40, 63, 91, 124, 162, 205, 253, 306, 364, 427, 495, 568, 646, 729, 817, 910, 1008, 1111, 1219, 1332, 1450, 1573, 1701, 1834, 1972, 2115, 2263, 2416, 2574, 2737, 2905, 3078, 3256, 3439, 3627, 3820, 4018, 4221, 4429, 4642, 4860, 5083, 5311, 5544
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OFFSET
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0,2
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COMMENTS
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Binomial transform of (1, 8, 5, 0, 0, 0, ...).
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LINKS
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FORMULA
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a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=1, a(1)=9, a(2)=22. - Harvey P. Dale, Sep 11 2015
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EXAMPLE
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a(2) = 22 = sum of row 2 terms of triangle A131894: (11 + 6 + 5).
a(2) = 22 = (1, 2, 1) dot (1, 8, 5) = (1 + 16 + 5).
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MAPLE
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {1, 9, 22}, 50] (* Harvey P. Dale, Sep 11 2015 *)
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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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EXTENSIONS
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STATUS
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approved
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