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A152997
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Twice 13-gonal numbers: a(n) = n*(11*n - 9).
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3
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0, 2, 26, 72, 140, 230, 342, 476, 632, 810, 1010, 1232, 1476, 1742, 2030, 2340, 2672, 3026, 3402, 3800, 4220, 4662, 5126, 5612, 6120, 6650, 7202, 7776, 8372, 8990, 9630, 10292, 10976, 11682, 12410, 13160, 13932, 14726, 15542, 16380, 17240, 18122, 19026, 19952, 20900, 21870, 22862, 23876
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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(n) = 11*n^2 - 9*n = A051865(n)*2.
G.f.: 2*x*(1 + 10*x)/(1-x)^3.
E.g.f.: x*(2 + 11*x)*exp(x). (End)
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MAPLE
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MATHEMATICA
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PROG
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(Magma) [n*(11*n-9): n in [0..50]];
(Sage) [n*(11*n-9) for n in (0..50)] # G. C. Greubel, Sep 01 2019
(GAP) List([0..50], n-> n*(11*n-9)); # G. C. Greubel, Sep 01 2019
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CROSSREFS
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Cf. numbers of the form n*(n*k - k + 4))/2 listed in A226488 (this sequence is the case k=22). - Bruno Berselli, Jun 10 2013
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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