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 A229620 #19 Mar 20 2022 18:28:40
%S A229620 0,6,38,116,256,478,798,1236,1808,2534,3430,4516,5808,7326,9086,11108,
%T A229620 13408,16006,18918,22164,25760,29726,34078,38836,44016,49638,55718,
%U A229620 62276,69328,76894,84990,93636,102848,112646,123046,134068,145728,158046,171038,184724,199120,214246,230118,246756,264176,282398,301438,321316,342048,363654
%N A229620 Incorrect version of A045949.
%C A229620 Arises from the formula in Problem 11 of Zhuravlev and Samovol (2012) paper, which incorrectly claims it to produce sequence A045949. Terms a(n) for n<=3 match those of A045949 but afterwards the two sequences diverge. Nevertheless these sequences satisfy the same linear recurrent relation.
%H A229620 V. Zhuravlev and P. Samovol, <a href="http://kvant.ras.ru/pdf/2012/2012-01.pdf">Mathematical enigmas of king Solomon's stamp</a>, Kvant 1 (2012), 40-43. (in Russian)
%H A229620 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2,-2,3,-1).
%F A229620 For even n, a(n) = n*(6*n^2+9*n-4)/2; for odd n, a(n) = (n+1)*(6*n^2+3*n+1)/2 - 4*n.
%F A229620 For n>=4, a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-2) + 3*a(n-3) - a(n-4).
%F A229620 a(n) = (1-(-1)^n-8*n+18*n^2+12*n^3)/4. G.f.: -2*x*(2*x+1)*(x^2-4*x-3) / ((x-1)^4*(x+1)). - _Colin Barker_, Sep 29 2013
%F A229620 E.g.f.: (x*(11 + 27*x + 6*x^2)*cosh(x) + (1 + 11*x + 27*x^2 + 6*x^3)*sinh(x))/2. - _Stefano Spezia_, Mar 20 2022
%o A229620 (PARI) { a(n) = if(n%2, (n+1)*(6*n^2+3*n+1)/2- 4*n, n*(6*n^2+9*n-4)/2 ) }
%Y A229620 Cf. A045949.
%K A229620 nonn,easy
%O A229620 0,2
%A A229620 _Max Alekseyev_, Sep 26 2013