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Search: id:A138778
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| A138778 |
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Triangle read by rows: T(n,k)=k*binomial(n-2k,3k) (n>=5, 1<=k<=n/5). |
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1
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| 1, 4, 10, 20, 35, 56, 2, 84, 14, 120, 56, 165, 168, 220, 420, 286, 924, 3, 364, 1848, 30, 455, 3432, 165, 560, 6006, 660, 680, 10010, 2145, 816, 16016, 6006, 4, 969, 24752, 15015, 52, 1140, 37128, 34320, 364
(list; graph; listen)
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OFFSET
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5,2
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COMMENT
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Row n contains floor(n/5) terms.
Row sums yield A137359.
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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) end proc: for n from 5 to 22 do seq(T(n, k), k=1..(1/5)*n) end do; # yields sequence in triangular form
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CROSSREFS
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Cf. A137359.
Adjacent sequences: A138775 A138776 A138777 this_sequence A138779 A138780 A138781
Sequence in context: A008144 A038406 A127764 this_sequence A038409 A090579 A000292
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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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