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Search: id:A138780
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| A138780 |
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Triangle read by rows: T(n,k)=k*binomial(n-2k,3k+2) (n>=7, 1<=k<=(n-2)/5). |
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| 1, 6, 21, 56, 126, 252, 2, 462, 18, 792, 90, 1287, 330, 2002, 990, 3003, 2574, 3, 4368, 6006, 36, 6188, 12870, 234, 8568, 25740, 1092, 11628, 48620, 4095, 15504, 87516, 13104, 4, 20349, 151164, 37128, 60
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OFFSET
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7,2
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COMMENT
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Row n contains floor((n-2)/5) terms.
Row sums yield A137361.
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REFERENCES
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D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.
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MAPLE
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T:=proc(n, k) options operator, arrow: k*binomial(n-2*k, 3*k+2) end proc: for n from 7 to 23 do seq(T(n, k), k=1..(n-2)*1/5) end do; # yields sequence in triangular form
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CROSSREFS
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Cf. A137361.
Sequence in context: A050190 A008498 A015640 this_sequence A108907 A008488 A120478
Adjacent sequences: A138777 A138778 A138779 this_sequence A138781 A138782 A138783
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KEYWORD
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nonn,tabf
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), May 10 2008
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