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A152995
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Twice 11-gonal numbers: a(n) = n*(9*n-7).
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3
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0, 2, 22, 60, 116, 190, 282, 392, 520, 666, 830, 1012, 1212, 1430, 1666, 1920, 2192, 2482, 2790, 3116, 3460, 3822, 4202, 4600, 5016, 5450, 5902, 6372, 6860, 7366, 7890, 8432, 8992, 9570, 10166, 10780, 11412, 12062, 12730, 13416, 14120
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OFFSET
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0,2
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LINKS
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FORMULA
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a(0)=0, a(1)=2, a(2)=22, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, Nov 02 2011
G.f.: 2*x*(1+8*x)/(1-x)^3.
E.g.f.: x*(2+9*x)*exp(x). (End)
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MAPLE
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MATHEMATICA
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Table[n(9n-7), {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 2, 22}, 40] (* Harvey P. Dale, Nov 02 2011 *)
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PROG
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(Magma) [n*(9*n-7): n in [0..50]];
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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