A153373 Number of zig-zag paths from top to bottom of a rectangle of width 11 with 2n-1 rows whose color is not that of the top right corner.
5, 18, 66, 244, 906, 3372, 12566, 46860, 174810, 652252, 2433942, 9083004, 33897050, 126503148, 472111446, 1761934444, 6575609946, 24540472572, 91586214806, 341804255580, 1275630545370, 4760717401612, 17767238012502
Offset: 1
Links
- Joseph Myers, BMO 2008--2009 Round 1 Problem 1---Generalisation
- Index entries for linear recurrences with constant coefficients, signature (6, -9, 2).
Formula
Empirical G.f.: x*(5-12*x+3*x^2)/(1-6*x+9*x^2-2*x^3). - Colin Barker, Jan 04 2012