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 A105577 #23 May 22 2025 15:52:58
%S A105577 1,5,6,-1,-10,-5,18,31,-2,-61,-54,71,182,43,-318,-401,238,1043,570,
%T A105577 -1513,-2650,379,5682,4927,-6434,-16285,-3414,29159,35990,-22325,
%U A105577 -94302,-49649,138958,238259,-39654,-516169,-436858,595483,1469202,278239,-2660162,-3216637,2103690,8536967
%N A105577 a(n) = 2*a(n-1) - 3*a(n-2) + 2*a(n-3) with a(0) = 1, a(1) = 5, a(2) = 6.
%C A105577 Floretion Algebra Multiplication Program, FAMP Code: 2lesseq[.5'j + .5'k + .5j' + .5k' + .5'ii' + .5e]
%H A105577 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,-3,2).
%F A105577 G.f.: (1+3*x-x^2)/((1-x)*(1-x+2*x^2)). - _Colin Barker_, Mar 26 2012
%F A105577 E.g.f.: exp(x/2)*(21*exp(x/2) - 7*cos(sqrt(7)*x/2) + 15*sqrt(7)*sin(sqrt(7)*x/2))/14. - _Stefano Spezia_, May 22 2025
%t A105577 LinearRecurrence[{2,-3,2},{1,5,6},50] (* _Harvey P. Dale_, Apr 13 2019 *)
%Y A105577 Cf. A002249, A014551, A105578.
%Y A105577 Equals (1/4) [A107920(n+4) + 2*A107920(n-1) + 3].
%K A105577 sign,easy
%O A105577 0,2
%A A105577 _Creighton Dement_, Apr 14 2005