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 A206372 #17 Jun 30 2023 18:57:29 %S A206372 13,55,223,895,3583,14335,57343,229375,917503,3670015,14680063, %T A206372 58720255,234881023,939524095,3758096383,15032385535,60129542143, %U A206372 240518168575,962072674303,3848290697215,15393162788863,61572651155455,246290604621823,985162418487295 %N A206372 a(n) = 14 * 4^n - 1. %H A206372 G. C. Greubel, <a href="/A206372/b206372.txt">Table of n, a(n) for n = 0..1000</a> %H A206372 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5, -4). %F A206372 a(n) = 7*2^(2*n+1) - 1. %F A206372 a(n) = (A199207(n+1) -3)/2 for n>=0. %F A206372 From _G. C. Greubel_, Jan 05 2023: (Start) %F A206372 a(n) = A005009(2*n+1) - 1. %F A206372 G.f.: (13 - 10*x)/((1-x)*(1-4*x)). %F A206372 E.g.f.: 14*exp(4*x) - exp(x). (End) %t A206372 7*2^(2*Range[0,50]+1)-1 (* _G. C. Greubel_, Jan 05 2023 *) %o A206372 (Magma) [14*4^n-1 : n in [0..30]]; %o A206372 (PARI) a(n)=14*4^n - 1 \\ _Charles R Greathouse IV_, May 05 2014 %o A206372 (SageMath) [7*2^(2*n+1)-1 for n in range(51)] # _G. C. Greubel_, Jan 05 2023 %Y A206372 Cf. A005009, A199207. %K A206372 nonn,easy %O A206372 0,1 %A A206372 _Brad Clardy_, Feb 07 2012