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 A332491 #17 Apr 20 2025 11:35:38
%S A332491 3,1,2,7,15,32,71,157,346,763,1683,3712,8187,18057,39826,87839,193735,
%T A332491 427296,942431,2078597,4584490,10111411,22301419,49187328,108486067,
%U A332491 239273553,527734434,1163954935,2567183423,5662101280,12488157495,27543498413
%N A332491 a(n) = 2*a(n-1) + a(n-3), where a(0) = 3, a(1) = 1, a(2) = 2.
%H A332491 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,1).
%F A332491 a(n) = 2*a(n-1) + a(n-3).
%F A332491 a(n) = A052980(n) + 2*A008998(n-3).
%F A332491 a(n) = A008998(n-1) + 3*A008998(n-3).
%F A332491 G.f.: (5x-3)/(x^3+2*x-1).
%t A332491 LinearRecurrence[{2,0,1},{3,1,2},40] (* _Harvey P. Dale_, Apr 20 2025 *)
%K A332491 nonn,easy
%O A332491 0,1
%A A332491 _Michael Tulskikh_, Feb 13 2020