A153364 Number of zig-zag paths from top to bottom of a rectangle of width 9 with n rows whose color is not that of the top right corner

4, 8, 14, 28, 50, 100, 180, 360, 650, 1300, 2350, 4700, 8500, 17000, 30750, 61500, 111250, 222500, 402500, 805000, 1456250, 2912500, 5268750, 10537500, 19062500, 38125000, 68968750, 137937500, 249531250, 499062500, 902812500, 1805625000

Offset

1,1

Links

Table of n, a(n) for n=1..32.

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

Formula

Empirical G.f.: x*(4+8*x-6*x^2-12*x^3)/(1-5*x^2+5*x^4). - Colin Barker, Jan 04 2012

Crossrefs

A153362, A153363, A153365, A153366, A153367

Sequence in context: A129080 A138643 A183977 * A124743 A188575 A324585

Adjacent sequences: A153361 A153362 A153363 * A153365 A153366 A153367

Keyword

easy,nonn

Author

Joseph Myers, Dec 24 2008

Status

approved