This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A152965 #43 Dec 27 2024 21:03:10
%S A152965 0,2,24,66,128,210,312,434,576,738,920,1122,1344,1586,1848,2130,2432,
%T A152965 2754,3096,3458,3840,4242,4664,5106,5568,6050,6552,7074,7616,8178,
%U A152965 8760,9362,9984,10626,11288,11970,12672,13394,14136,14898,15680,16482,17304,18146,19008
%N A152965 Twice 12-gonal numbers: a(n) = 2*n*(5*n-4).
%H A152965 Vincenzo Librandi, <a href="/A152965/b152965.txt">Table of n, a(n) for n = 0..1000</a>
%H A152965 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A152965 a(n) = 2*A051624(n).
%F A152965 From _Vincenzo Librandi_, Jul 10 2012: (Start)
%F A152965 G.f.: 2*x*(1+9*x)/(1-x)^3.
%F A152965 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). (End)
%F A152965 From _Elmo R. Oliveira_, Dec 27 2024: (Start)
%F A152965 E.g.f.: 2*exp(x)*x*(1 + 5*x).
%F A152965 a(n) = n + A051874(n). (End)
%t A152965 Table[10*n^2-8*n,{n,0,50}] (* _Vincenzo Librandi_, Jul 10 2012 *)
%t A152965 LinearRecurrence[{3,-3,1},{0,2,24},60] (* _Harvey P. Dale_, Apr 18 2016 *)
%o A152965 (Magma) [10*n^2-8*n: n in [0..50]]; // _Klaus Brockhaus_, Nov 27 2010
%o A152965 (PARI) a(n)=2*n*(5*n-4) \\ _Charles R Greathouse IV_, Oct 07 2015
%Y A152965 Cf. A051624 (12-gonal numbers), A051874.
%Y A152965 Cf. numbers of the form n*(n*k - k + 4)/2 listed in A226488 (this sequence is the case k=20). - _Bruno Berselli_, Jun 10 2013
%K A152965 easy,nonn
%O A152965 0,2
%A A152965 _Omar E. Pol_, Dec 21 2008