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 A202408 #17 Jan 18 2013 08:29:20 %S A202408 1,2,32,768,49152,1,56623104,3170893824,541165879296,175337744891904, %T A202408 28054039182704640,29389945810452480,2844006276185865584640, %U A202408 147888326361665010401280,25765432859454526256578560,83480002464632665071314534400 %N A202408 Denominator of series coefficients for Archimedes' spiral which transforms into Galileo's spiral. %C A202408 Numerators are listed in A202407 which is the main entry for these sequences. %t A202408 km = 16; a[0] = 0; r[t_] = Sum[a[k] t^(2 k), {k, 0, km}]; coes = CoefficientList[Series[r'[t]^2 + r[t]^2 - t^2 , {t, 0, 2 km}], t] // Union // Rest; Table[a[k], {k, 0, km}] /. Solve[Thread[coes == 0] ] // Last // Most // Denominator (* _Jean-François Alcover_, Jan 18 2013 *) %K A202408 nonn,frac %O A202408 0,2 %A A202408 _Mikhail Gaichenkov_, Dec 19 2011 %E A202408 Corrected and extended by _Max Alekseyev_, Dec 19 2011