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 A153369 #12 Sep 25 2024 16:33:52
%S A153369 6,10,20,36,72,132,264,488,976,1812,3624,6744,13488,25132,50264,93720,
%T A153369 187440,349620,699240,1304504,2609008,4867884,9735768,18166008,
%U A153369 36332016,67794100,135588200,253006296,506012592,944222892,1888445784,3523868888
%N A153369 Number of zig-zag paths from top to bottom of a rectangle of width 11 with n rows whose color is that of the top right corner.
%H A153369 Joseph Myers, <a href="http://www.polyomino.org.uk/publications/2008/bmo1-2009-q1.pdf">BMO 2008--2009 Round 1 Problem 1---Generalisation</a>
%H A153369 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0, 6, 0, -9, 0, 2).
%F A153369 Empirically, g.f. -2*x*(3+5*x-8*x^2-12*x^3+3*x^4+3*x^5) / ( (2*x^2-1)*(x^4-4*x^2+1) ) with a(n)= +6*a(n-2) -9*a(n-4) +2*a(n-6). - _R. J. Mathar_, Jun 16 2011
%t A153369 LinearRecurrence[{0,6,0,-9,0,2},{6,10,20,36,72,132},40] (* _Harvey P. Dale_, Sep 25 2024 *)
%Y A153369 A153368, A153370, A153371, A153372, A153373
%K A153369 easy,nonn
%O A153369 1,1
%A A153369 _Joseph Myers_, Dec 24 2008