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 A013712 #26 Aug 27 2024 18:02:31 %S A013712 7,343,16807,823543,40353607,1977326743,96889010407,4747561509943, %T A013712 232630513987207,11398895185373143,558545864083284007, %U A013712 27368747340080916343,1341068619663964900807,65712362363534280139543,3219905755813179726837607,157775382034845806615042743 %N A013712 a(n) = 7^(2*n + 1). %H A013712 Vincenzo Librandi, <a href="/A013712/b013712.txt">Table of n, a(n) for n = 0..150</a> %H A013712 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013712 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (49). %F A013712 From _Philippe Deléham_, Nov 24 2008: (Start) %F A013712 a(n) = 49*a(n-1); a(0)=7. %F A013712 G.f.: 7/(1-49*x). %F A013712 a(n) = 7*A087752(n). (End) %F A013712 From _Elmo R. Oliveira_, Aug 27 2024: (Start) %F A013712 E.g.f.: 7*exp(49*x). %F A013712 a(n) = A000420(A005408(n)). (End) %t A013712 NestList[49#&,7,20] (* _Harvey P. Dale_, Jul 15 2019 *) %o A013712 (Magma) [7^(2*n+1): n in [0..20]]; // _Vincenzo Librandi_, May 26 2011 %o A013712 (PARI) a(n)=7^(2*n+1) \\ _Charles R Greathouse IV_, Jul 11 2016 %Y A013712 Cf. A000420, A005408, A087752. %K A013712 nonn,easy %O A013712 0,1 %A A013712 _N. J. A. Sloane_