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 A162254 #29 Feb 10 2025 04:38:34
%S A162254 4,19,51,106,190,309,469,676,936,1255,1639,2094,2626,3241,3945,4744,
%T A162254 5644,6651,7771,9010,10374,11869,13501,15276,17200,19279,21519,23926,
%U A162254 26506,29265,32209,35344,38676,42211,45955,49914,54094,58501,63141
%N A162254 a(n) = n*(2*n^2 + 5*n + 1)/2.
%C A162254 Row sums from A083487.
%C A162254 Row 2 of the convolution array A213831. - _Clark Kimberling_, Jul 04 2012
%C A162254 Number of CNF statements for checking whether a 3-colored n X n grid has no monochromatic L. See Mammel et al. - _Michel Marcus_, Feb 10 2025
%H A162254 Vincenzo Librandi, <a href="/A162254/b162254.txt">Table of n, a(n) for n = 1..1000</a>
%H A162254 Isaac Mammel, William Smith, and Carl Yerger, <a href="https://arxiv.org/abs/2502.05162">Ramsey Theory on the Integer Grid: The "L" Problem</a>, arXiv:2502.05162 [math.CO], 2025. See p. 14.
%H A162254 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A162254 From _Vincenzo Librandi_, Mar 04 2012: (Start)
%F A162254 G.f.: x*(4 + 3*x - x^2)/(1-x)^4.
%F A162254 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
%t A162254 LinearRecurrence[{4,-6,4,-1}, {4, 19, 51, 106}, 50] (* or *) CoefficientList[Series[(4+3*x-x^2)/(1-x)^4,{x,0,40}],x] (* _Vincenzo Librandi_, Mar 04 2012 *)
%o A162254 (PARI) a(n)=n*(5*n+1)/2+n^3 \\ _Charles R Greathouse IV_, Jan 11 2012
%K A162254 nonn,easy
%O A162254 1,1
%A A162254 _Vincenzo Librandi_, Jun 29 2009
%E A162254 New name from _Charles R Greathouse IV_, Jan 11 2012