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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
5, 18, 66, 244, 906, 3372, 12566, 46860, 174810, 652252, 2433942, 9083004, 33897050, 126503148, 472111446, 1761934444, 6575609946, 24540472572, 91586214806, 341804255580, 1275630545370, 4760717401612, 17767238012502
OFFSET
1,1
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
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Joseph Myers, Dec 24 2008
STATUS
approved