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Search: id:A091144
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| A091144 |
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Binomial(n^2,n)/(1+(n-1)n). |
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+0
1
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| 1, 1, 2, 12, 140, 2530, 62832, 1997688, 77652024, 3573805950, 190223180840, 11502251937176, 779092434772236, 58448142042957576, 4811642166029230560, 431306008583779517040, 41820546066482630185200
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Diagonal of array T(n,k)=binom(kn,n)/(1+(k-1)n).
Number of paths up and left from (0,0) to (n^2-n,n) where x/y<=n-1 for all intermediate points. - Henry Bottomley (se16(AT)btinternet.com), Dec 25 2003
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REFERENCES
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D. Merlini, R. Sprugnoli and M. C. Verri, The tennis ball problem, J. Combin. Theory, A 99 (2002), 307-344.
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FORMULA
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a(n) =A014062(n)/A002061(n) =A062993(n-2, n) =A070914(n, n-1) =A071201(n, n^2-n) =A071201(n, n^2-n+1) =A071202(n, n^2-n+1). - Henry Bottomley (se16(AT)btinternet.com), Dec 25 2003
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CROSSREFS
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Sequence in context: A117513 A119819 A093543 this_sequence A087800 A009747 A067601
Adjacent sequences: A091141 A091142 A091143 this_sequence A091145 A091146 A091147
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Dec 22 2003
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