

A153371


Number of zigzag paths from top to bottom of a rectangle of width 11 with 2n rows whose color is that of the top right corner.


4



10, 36, 132, 488, 1812, 6744, 25132, 93720, 349620, 1304504, 4867884, 18166008, 67794100, 253006296, 944222892, 3523868888, 13151219892, 49080945144, 183172429612, 683608511160, 2551261090740, 9521434803224, 35534476025004
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..23.
Joseph Myers, BMO 20082009 Round 1 Problem 1Generalisation


FORMULA

Empirical: G.f. 2*x*(512*x+3*x^2) / ( (2*x1)*(x^24*x+1) ) with a(n)= +6*a(n1) 9*a(n2) +2*a(n3) and a(n) = (2^n+4*A001075(n+1))/3.  R. J. Mathar, Jun 16 2011


CROSSREFS

A153368, A153369, A153370, A153372, A153373
Sequence in context: A118415 A051959 A117327 * A248463 A169880 A282554
Adjacent sequences: A153368 A153369 A153370 * A153372 A153373 A153374


KEYWORD

easy,nonn


AUTHOR

Joseph Myers, Dec 24 2008


STATUS

approved



