A153365 Number of zig-zag paths from top to bottom of a rectangle of width 9 with 2n rows whose color is that of the top right corner.

8, 28, 100, 360, 1300, 4700, 17000, 61500, 222500, 805000, 2912500, 10537500, 38125000, 137937500, 499062500, 1805625000, 6532812500, 23635937500, 85515625000, 309398437500, 1119414062500, 4050078125000, 14653320312500

Offset

1,1

Links

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

Joseph Myers, BMO 2008--2009 Round 1 Problem 1---Generalisation

Formula

Empirical G.f.: x*(8-12*x)/(1-5*x+5*x^2). - Colin Barker, Jan 04 2012

Crossrefs

A153362, A153363, A153364, A153366, A153367

Sequence in context: A054114 A305907 A110687 * A317149 A316879 A220710

Adjacent sequences: A153362 A153363 A153364 * A153366 A153367 A153368

Keyword

nonn,easy

Author

Joseph Myers, Dec 24 2008

Status

approved