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A187710
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a(n) = n^2 + n + 10.
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2
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10, 12, 16, 22, 30, 40, 52, 66, 82, 100, 120, 142, 166, 192, 220, 250, 282, 316, 352, 390, 430, 472, 516, 562, 610, 660, 712, 766, 822, 880, 940, 1002, 1066, 1132, 1200, 1270, 1342, 1416, 1492, 1570, 1650, 1732, 1816, 1902, 1990, 2080, 2172, 2266, 2362, 2460
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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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a(0)=10, a(1)=12, a(2)=16; for n>2, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, Jan 18 2014
G.f.: 2*(5 - 9*x + 5*x^2)/(1 - x)^3.
a(n) = Sum_{i=n-5..n+5} i*(i+1)/11. (End)
Sum_{n>=0} 1/a(n) = Pi*tanh(Pi*sqrt(39)/2)/sqrt(39). - Amiram Eldar, Jan 17 2021
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MATHEMATICA
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f[n_] := n^2 + n + 10; f[Range[0, 100]]
LinearRecurrence[{3, -3, 1}, {10, 12, 16}, 50] (* Harvey P. Dale, Jan 18 2014 *)
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PROG
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(Magma) [n^2 + n + 10: n in [0..50]]; // G. C. Greubel, Nov 06 2018
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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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