A152997 Twice 13-gonal numbers: a(n) = n*(11*n - 9).
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
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Crossrefs
Cf. A051865 (13-gonal numbers).
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
Programs
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GAP
List([0..50], n-> n*(11*n-9)); # G. C. Greubel, Sep 01 2019
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Magma
[n*(11*n-9): n in [0..50]];
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Maple
seq(n*(11*n-9), n=0..50); # G. C. Greubel, Sep 01 2019
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Mathematica
Table[n*(11*n-9), {n,0,50}] (* G. C. Greubel, Sep 01 2019 *) -
PARI
a(n)=n*(11*n-9) \\ Charles R Greathouse IV, Jun 17 2017
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Sage
[n*(11*n-9) for n in (0..50)] # G. C. Greubel, Sep 01 2019
Formula
a(n) = 11*n^2 - 9*n = A051865(n)*2.
a(n) = a(n-1) + 22*n - 20 (with a(0)=0). - Vincenzo Librandi, Nov 27 2010
From G. C. Greubel, Sep 01 2019: (Start)
G.f.: 2*x*(1 + 10*x)/(1-x)^3.
E.g.f.: x*(2 + 11*x)*exp(x). (End)
Extensions
Terms a(39) onward added by G. C. Greubel, Sep 01 2019