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Search: id:A138775
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| A138775 |
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Triangle read by rows: T(n,k)=binomial(n-2k,3k) (n>=0, 0<=k<=n/5). |
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1
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| 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 10, 1, 20, 1, 35, 1, 56, 1, 1, 84, 7, 1, 120, 28, 1, 165, 84, 1, 220, 210, 1, 286, 462, 1, 1, 364, 924, 10, 1, 455, 1716, 55, 1, 560, 3003, 220, 1, 680, 5005, 715, 1, 816, 8008, 2002, 1
(list; graph; listen)
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OFFSET
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0,9
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COMMENT
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Row n contains 1+floor(n/5) terms.
Row sums yield A137356.
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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: binomial(n-2*k, 3*k) end proc: for n from 0 to 20 do seq(T(n, k), k=0..(1/5)*n) end do; # yields sequence in triangular form
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CROSSREFS
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Cf. A137356.
Sequence in context: A065045 A064947 A059926 this_sequence A121529 A006370 A108759
Adjacent sequences: A138772 A138773 A138774 this_sequence A138776 A138777 A138778
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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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