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 A350054 #25 Jan 28 2024 09:01:53
%S A350054 113,7281,466033,29826161,1908874353,122167958641,7818749353073,
%T A350054 500399958596721,32025597350190193,2049638230412172401,
%U A350054 131176846746379033713,8395318191768258157681,537300364273168522091633,34387223313482785413864561
%N A350054 a(n) = (4^(3*n+2) - 7)/9.
%C A350054 Bisection of A350053, namely the even part. The odd part is given in A228871.
%H A350054 Winston de Greef, <a href="/A350054/b350054.txt">Table of n, a(n) for n = 1..551</a>
%H A350054 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (65,-64).
%F A350054 a(n) = (2^(6*n+4) - 7)/9, n >= 1.
%F A350054 G.f.: x*(113 - 64*x)/((1 - x)*(1 - 64*x)).
%F A350054 a(n) = 112*A133853(n) + 1. - _Hugo Pfoertner_, Jan 21 2022
%t A350054 Table[(4^(3*n + 2) - 7)/9, {n, 1, 14}] (* _Amiram Eldar_, Jan 21 2022 *)
%o A350054 (PARI) a(n) = (4^(3*n+2) - 7)/9 \\ _Winston de Greef_, Jan 27 2024
%Y A350054 Cf. A133853, A228871, A350053.
%K A350054 nonn,easy
%O A350054 1,1
%A A350054 _Wolfdieter Lang_, Jan 20 2022