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 A343176 #21 Apr 27 2021 02:15:06 %S A343176 3,8,23,77,281,1073,4193,16577,65921,262913,1050113,4197377,16783361, %T A343176 67121153,268460033,1073790977,4295065601,17180065793,68719869953, %U A343176 274878693377,1099513200641,4398049656833,17592192335873,70368756760577,281475001876481,1125899957174273,4503599728033793 %N A343176 a(0)=3; for n > 0, a(n) = 2^(2*n) + 3*2^(n-1) + 1. %C A343176 A bisection of A257418. Apart from first term, same as A036562. %H A343176 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8). %F A343176 From _Chai Wah Wu_, Apr 26 2021: (Start) %F A343176 a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3) for n > 3. %F A343176 G.f.: -(4*x - 3)*(x^2 + 3*x - 1)/((x - 1)*(2*x - 1)*(4*x - 1)). (End) %Y A343176 Cf. A257418, A036562, A343175. %K A343176 nonn,easy %O A343176 0,1 %A A343176 _N. J. A. Sloane_, Apr 26 2021 %E A343176 a(17)-a(26) from _Martin Ehrenstein_, Apr 26 2021