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 A013826 #29 Feb 20 2025 19:35:20 %S A013826 3,729,177147,43046721,10460353203,2541865828329,617673396283947, %T A013826 150094635296999121,36472996377170786403,8862938119652501095929, %U A013826 2153693963075557766310747,523347633027360537213511521,127173474825648610542883299603,30903154382632612361920641803529 %N A013826 a(n) = 3^(5*n + 1). %H A013826 Vincenzo Librandi, <a href="/A013826/b013826.txt">Table of n, a(n) for n = 0..200</a> %H A013826 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013826 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (243). %F A013826 From _Philippe Deléham_, Nov 26 2008: (Start) %F A013826 a(n) = 243*a(n-1); a(0)=3. %F A013826 G.f.: 3/(1-243*x). (End) %F A013826 E.g.f.: 3*exp(243*x). - _Stefano Spezia_, Feb 20 2025 %t A013826 NestList[243#&,3,20] (* _Harvey P. Dale_, Jan 26 2013 *) %o A013826 (Magma) [3^(5*n+1): n in [0..15]]; // _Vincenzo Librandi_, Jul 07 2011 %o A013826 (Maxima) makelist(3^(5*n+1),n,0,20); /* _Martin Ettl_, Oct 21 2012 */ %o A013826 (PARI) a(n)=3^(5*n+1) \\ _Charles R Greathouse IV_, Jul 11 2016 %Y A013826 Cf. A000244, A016861. %K A013826 nonn,easy %O A013826 0,1 %A A013826 _N. J. A. Sloane_