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

1,1

Links

Table of n, a(n) for n=1..23.

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

Crossrefs

Cf. A153368-A153372.

Sequence in context: A147535 A184309 A051944 * A225015 A371871 A166677

Adjacent sequences: A153370 A153371 A153372 * A153374 A153375 A153376

Keyword

nonn,easy

Author

Joseph Myers, Dec 24 2008

Status

approved