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 A343175 #24 Aug 04 2024 17:36:49
%S A343175 2,5,13,41,145,545,2113,8321,33025,131585,525313,2099201,8392705,
%T A343175 33562625,134234113,536903681,2147549185,8590065665,34360000513,
%U A343175 137439477761,549756862465,2199025352705,8796097216513,35184380477441,140737505132545,562949986975745,2251799880794113
%N A343175 a(0)=2; for n > 0, a(n) = 2^(2*n-1) + 2^n + 1.
%C A343175 A bisection of A257418. Apart from first term, same as A085601.
%H A343175 Harvey P. Dale, <a href="/A343175/b343175.txt">Table of n, a(n) for n = 0..1000</a>
%H A343175 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).
%F A343175 From _Chai Wah Wu_, Apr 26 2021: (Start)
%F A343175 a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3) for n > 3.
%F A343175 G.f.: (-4*x^3 - 6*x^2 + 9*x - 2)/((x - 1)*(2*x - 1)*(4*x - 1)). (End)
%t A343175 LinearRecurrence[{7,-14,8},{2,5,13,41},30] (* _Harvey P. Dale_, Aug 04 2024 *)
%Y A343175 Cf. A257418, A085601, A343176.
%K A343175 nonn,easy
%O A343175 0,1
%A A343175 _N. J. A. Sloane_, Apr 26 2021
%E A343175 a(18)-a(26) from _Martin Ehrenstein_, Apr 26 2021