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Search: id:A118649
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A118649 Row sums for A106597. +0
1
1, 2, 5, 12, 30, 74, 184, 456, 1132, 2808, 6968, 17288, 42896, 106432, 264080, 655232, 1625760, 4033824, 10008704, 24833536, 61616832, 152883328, 379333248, 941199488, 2335298816, 5794330112, 14376858880, 35671780352, 88508618240 (list; graph; listen)
OFFSET

0,2

COMMENT

For n>=2, a(n)= Number of "stable LEGO walls" (i.e., walls in which seams don't match up from one level to the next) of width 7 and height n-1 when using bricks of length 2, 3, and 4. For example, there are a(2)=5 stable LEGO walls of height 1 and they are {[2,2,3],[2,3,2],[3,2,2],[3,4],[4,3]}. [From Emilie Hogan (eahogan(AT)math.rutgers.edu), Oct 16 2009]

CROSSREFS

Adjacent sequences: A118646 A118647 A118648 this_sequence A118650 A118651 A118652

Sequence in context: A157748 A046170 A062423 this_sequence A033482 A054341 A000106

KEYWORD

nonn,new

AUTHOR

Joshua Zucker (joshua.zucker(AT)stanfordalumni.org), May 10 2006

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Last modified November 9 12:23 EST 2009. Contains 166233 sequences.


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