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 A002066 #42 Apr 02 2025 15:16:56 %S A002066 10,40,160,640,2560,10240,40960,163840,655360,2621440,10485760, %T A002066 41943040,167772160,671088640,2684354560,10737418240,42949672960, %U A002066 171798691840,687194767360,2748779069440,10995116277760,43980465111040,175921860444160,703687441776640,2814749767106560 %N A002066 a(n) = 10*4^n. %H A002066 Vincenzo Librandi, <a href="/A002066/b002066.txt">Table of n, a(n) for n = 0..500</a> %H A002066 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A002066 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (4). %F A002066 From _Philippe Deléham_, Nov 23 2008: (Start) %F A002066 a(n) = 4*a(n-1), n > 0; a(0)=10. %F A002066 G.f.: 10/(1-4*x). (End) %F A002066 From _Elmo R. Oliveira_, Apr 02 2025: (Start) %F A002066 E.g.f.: 10*exp(4*x). %F A002066 a(n) = 5*A004171(n) = 2*A003947(n+1) = A020714(n)*A000079(n+1). (End) %t A002066 10*4^Range[0, 100] (* _Vladimir Joseph Stephan Orlovsky_, Jun 09 2011 *) %o A002066 (Magma) [10*4^n: n in [0..30]]; // _Vincenzo Librandi_, May 19 2011 %o A002066 (PARI) a(n)=10*4^n \\ _Charles R Greathouse IV_, Apr 18 2012 %Y A002066 Pairwise sums of A081294. %Y A002066 Cf. A000079, A003947, A004171, A020714. %K A002066 nonn,easy %O A002066 0,1 %A A002066 _N. J. A. Sloane_