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 A013714 #26 Aug 26 2024 20:18:03 %S A013714 9,729,59049,4782969,387420489,31381059609,2541865828329, %T A013714 205891132094649,16677181699666569,1350851717672992089, %U A013714 109418989131512359209,8862938119652501095929,717897987691852588770249,58149737003040059690390169,4710128697246244834921603689 %N A013714 a(n) = 9^(2*n + 1). %H A013714 Vincenzo Librandi, <a href="/A013714/b013714.txt">Table of n, a(n) for n = 0..150</a> %H A013714 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013714 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (81). %F A013714 From _Philippe Deléham_, Nov 25 2008: (Start) %F A013714 a(n) = 81*a(n-1); a(0)=9. %F A013714 G.f.: 9/(1-81*x). (End) %F A013714 From _Elmo R. Oliveira_, Aug 26 2024: (Start) %F A013714 E.g.f.: 9*exp(81*x). %F A013714 a(n) = 3*A013778(n) = A001019(A005408(n)). (End) %t A013714 9^(2*Range[0,20]+1) (* or *) NestList[81#&,9,20] (* _Harvey P. Dale_, May 25 2020 *) %o A013714 (Magma) [9^(2*n+1): n in [0..20]]; // _Vincenzo Librandi_, May 26 2011 %o A013714 (PARI) a(n)=9^(2*n+1) \\ _Charles R Greathouse IV_, Jul 11 2016 %Y A013714 Cf. A001019, A005408, A013778. %K A013714 nonn,easy %O A013714 0,1 %A A013714 _N. J. A. Sloane_