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 A153370 #11 Jul 03 2023 11:02:48 %S A153370 5,10,18,36,66,132,244,488,906,1812,3372,6744,12566,25132,46860,93720, %T A153370 174810,349620,652252,1304504,2433942,4867884,9083004,18166008, %U A153370 33897050,67794100,126503148,253006296,472111446,944222892,1761934444,3523868888 %N A153370 Number of zig-zag paths from top to bottom of a rectangle of width 11 with n rows whose color is not that of the top right corner. %H A153370 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 A153370 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0, 6, 0, -9, 0, 2). %F A153370 Empirical: G.f. -x*(2*x+1)*(3*x^4-12*x^2+5) / ( (2*x^2-1)*(x^4-4*x^2+1) ) and a(n)= +6*a(n-2) -9*a(n-4) +2*a(n-6). - _R. J. Mathar_, Jun 16 2011 %Y A153370 A153368, A153369, A153372. Bisections: A153371, A153373. %K A153370 easy,nonn %O A153370 1,1 %A A153370 _Joseph Myers_, Dec 24 2008