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 A186030 #31 Sep 08 2022 08:45:55
%S A186030 0,5,23,54,98,155,225,308,404,513,635,770,918,1079,1253,1440,1640,
%T A186030 1853,2079,2318,2570,2835,3113,3404,3708,4025,4355,4698,5054,5423,
%U A186030 5805,6200,6608,7029,7463,7910,8370,8843,9329,9828,10340,10865,11403
%N A186030 a(n) = n*(13*n-3)/2.
%H A186030 Vincenzo Librandi, <a href="/A186030/b186030.txt">Table of n, a(n) for n = 0..1000</a>
%H A186030 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A186030 G.f.: x*(5+8*x)/(1-x)^3.
%F A186030 From _Bruno Berselli_, Sep 05 2011: (Start)
%F A186030 a(n) - a(-n) = -A008585(n).
%F A186030 a(n) + a(-n) = A152742(n). (End)
%F A186030 E.g.f.: (1/2)*(13*x^2 + 10*x)*exp(x). - _G. C. Greubel_, Jul 17 2017
%t A186030 Table[n (13n-3)/2,{n,0,60}] (* _Harvey P. Dale_, Feb 24 2011 *)
%o A186030 (Magma) [ n*(13*n-3)/2 : n in [0..42] ];
%o A186030 (PARI) a(n)=n*(13*n-3)/2 \\ _Charles R Greathouse IV_, Oct 07 2015
%Y A186030 Cf. numbers of the form n*(d*n+10-d)/2 indexed in A140090.
%Y A186030 Cf. A154609 (first differences).
%Y A186030 Cf. A008585, A152742.
%K A186030 nonn,easy
%O A186030 0,2
%A A186030 _Bruno Berselli_, Feb 11 2011