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Search: id:A078990
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| A078990 |
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Triangle arising from (4,2) tennis ball problem, read by rows. |
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+0
3
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| 1, 1, 2, 3, 1, 4, 10, 16, 22, 1, 6, 21, 52, 105, 158, 211, 1, 8, 36, 116, 301, 644, 1198, 1752, 2306, 1, 10, 55, 216, 678, 1784, 4088, 8144, 14506, 20868, 27230, 1, 12, 78, 360, 1320, 4064, 10896, 25872, 55354, 105704, 183284, 260864, 338444, 1, 14, 105
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Length of row n = 2n+1. Rows have been reversed.
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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 (Table A.1).
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LINKS
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D. Merlini, The Tennis Ball Problems
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EXAMPLE
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1; 1,2,3; 1,4,10,16,22; ...
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PROGRAM
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(PARI) T(n, k)=if(k<0|k>2*n, 0, if(n<1, k==0, sum(j=0, k, (j+1)*T(n-1, k-j))))
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CROSSREFS
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Final diagonal gives A079489. Row sums give A066357(n+1).
Sequence in context: A076732 A130152 A084608 this_sequence A079639 A104694 A125182
Adjacent sequences: A078987 A078988 A078989 this_sequence A078991 A078992 A078993
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KEYWORD
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tabf,nonn
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AUTHOR
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njas, Jan 20 2003
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