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 A153371 #10 Jul 03 2023 11:05:23 %S A153371 10,36,132,488,1812,6744,25132,93720,349620,1304504,4867884,18166008, %T A153371 67794100,253006296,944222892,3523868888,13151219892,49080945144, %U A153371 183172429612,683608511160,2551261090740,9521434803224,35534476025004 %N A153371 Number of zig-zag paths from top to bottom of a rectangle of width 11 with 2n rows whose color is that of the top right corner. %H A153371 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 A153371 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6, -9, 2). %F A153371 Empirical: G.f. -2*x*(5-12*x+3*x^2) / ( (2*x-1)*(x^2-4*x+1) ) with a(n)= +6*a(n-1) -9*a(n-2) +2*a(n-3) and a(n) = (2^n+4*A001075(n+1))/3. - _R. J. Mathar_, Jun 16 2011 %Y A153371 A153368, A153369, A153370, A153372, A153373 %K A153371 easy,nonn %O A153371 1,1 %A A153371 _Joseph Myers_, Dec 24 2008