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 A153372 #10 Jul 03 2023 11:06:35 %S A153372 6,20,72,264,976,3624,13488,50264,187440,699240,2609008,9735768, %T A153372 36332016,135588200,506012592,1888445784,7047737776,26302439784, %U A153372 98161890288,366344859224,1367217022320,5102522181480,19042869606448 %N A153372 Number of zig-zag paths from top to bottom of a rectangle of width 11 with 2n-1 rows whose color is that of the top right corner. %H A153372 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 A153372 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6, -9, 2). %F A153372 Empirical g.f. -2*x*(3-8*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+8*A001075(n))/3. - _R. J. Mathar_, Jun 16 2011 %Y A153372 A153368, A153369, A153370, A153371, A153373 %K A153372 easy,nonn %O A153372 1,1 %A A153372 _Joseph Myers_, Dec 24 2008