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 A153364 #18 Jul 22 2025 06:17:15 %S A153364 4,8,14,28,50,100,180,360,650,1300,2350,4700,8500,17000,30750,61500, %T A153364 111250,222500,402500,805000,1456250,2912500,5268750,10537500, %U A153364 19062500,38125000,68968750,137937500,249531250,499062500,902812500,1805625000 %N A153364 Number of zig-zag paths from top to bottom of a rectangle of width 9 with n rows whose color is not that of the top right corner. %H A153364 Joseph Myers, <a href="http://www.polyomino.org.uk/publications/2008/bmo1-2009-q1.pdf">BMO 2008--2009 Round 1 Problem 1---Generalisation</a> %F A153364 Empirical G.f.: x*(4+8*x-6*x^2-12*x^3)/(1-5*x^2+5*x^4). - _Colin Barker_, Jan 04 2012 %Y A153364 A153362, A153363, A153365, A153366, A153367 %K A153364 easy,nonn %O A153364 1,1 %A A153364 _Joseph Myers_, Dec 24 2008