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Search: id:A158687
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| A158687 |
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Riordan array (1/(1-x),x(1+x)^2/(1-x)). |
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+0
3
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| 1, 1, 1, 1, 4, 1, 1, 8, 7, 1, 1, 12, 24, 10, 1, 1, 16, 56, 49, 13, 1, 1, 20, 104, 160, 83, 16, 1, 1, 24, 168, 400, 351, 126, 19, 1, 1, 28, 248, 832, 1120, 656, 178, 22, 1, 1, 32, 344, 1520, 2912, 2561, 1102, 239, 25, 1
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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Row sums are A077936. Diagonal sums are A129847. Central terms are A059304.
Inverse of alternating signed version is A100326.
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FORMULA
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Number triangle T(n,k)=sum{j=0..n-k, C(n-j,k)*C(2k,j)}.
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EXAMPLE
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Number triangle begins
1,
1, 1,
1, 4, 1,
1, 8, 7, 1,
1, 12, 24, 10, 1,
1, 16, 56, 49, 13, 1,
1, 20, 104, 160, 83, 16, 1
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CROSSREFS
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Sequence in context: A119673 A144447 A051455 this_sequence A141541 A132789 A100754
Adjacent sequences: A158684 A158685 A158686 this_sequence A158688 A158689 A158690
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Mar 24 2009
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