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Search: id:A071094
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| A071094 |
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Number of ways to tile hexagon of edges n, n, n+1, n, n, n+1 with diamonds of side 1. |
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+0
1
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| 1, 3, 50, 4116, 1646568, 3184461423, 29706808370096, 1335119245893326400, 288882990167192721013376, 300792059519113653077154558000, 1506680146887473588202049621593937500, 36298820709557430183399305000196605531250000, 4205446372314569673006362329181090368935937500000000, 2342761095072644391194625697884219372917666852341417500000000
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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J. Propp, Enumeration of matchings: problems and progress, pp. 255-291 in L. J. Billera et al., eds, New Perspectives in Algebraic Combinatorics, Cambridge, 1999 (see page 261).
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LINKS
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J. Propp, Updated article
J. Propp, Enumeration of matchings: problems and progress, in L. J. Billera et al. (eds.), New Perspectives in Algebraic Combinatorics
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FORMULA
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Product_{i=0..a-1} Product_{j=0..b-1} Product_{k=0..c-1} (i+j+k+2)/(i+j+k+1) with a=b=n, c=n+1.
a(n)=Product{k=0..n, C(2n+k,n+k)/C(n+k,k)}; - Paul Barry (pbarry(AT)wit.ie), May 13 2008
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CROSSREFS
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Sequence in context: A099346 A075184 A078674 this_sequence A144987 A062216 A045489
Adjacent sequences: A071091 A071092 A071093 this_sequence A071095 A071096 A071097
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 28 2002
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