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 A013717 #22 Sep 08 2022 08:44:38 %S A013717 12,1728,248832,35831808,5159780352,743008370688,106993205379072, %T A013717 15407021574586368,2218611106740436992,319479999370622926848, %U A013717 46005119909369701466112,6624737266949237011120128 %N A013717 a(n) = 12^(2*n + 1). %H A013717 Vincenzo Librandi, <a href="/A013717/b013717.txt">Table of n, a(n) for n = 0..200</a> %H A013717 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013717 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (144). %F A013717 From _Philippe Deléham_, Nov 25 2008: (Start) %F A013717 a(n) = 144*a(n-1), a(0)=12. %F A013717 G.f.: 12/(1-144*x). (End) %p A013717 seq(12^(2*n+1),n=0..11); # _Nathaniel Johnston_, Jun 25 2011 %o A013717 (Magma) [12^(2*n+1): n in [0..15]]; // _Vincenzo Librandi_, Jun 26 2011 %o A013717 (PARI) a(n)=12^(2*n+1) \\ _Charles R Greathouse IV_, Jul 11 2016 %Y A013717 Bisection of A001021. %Y A013717 Cf. A013708-A013716, A013718-A013729. %K A013717 nonn,easy %O A013717 0,1 %A A013717 _N. J. A. Sloane_