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A158687
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Riordan array (1/(1-x),x(1+x)^2/(1-x)).
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2
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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; refs; listen; history; internal format)
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OFFSET
| 0,5
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COMMENTS
| Row sums are A077936. Diagonal sums are A129847. Central terms are A059304.
Inverse of alternating signed version is A100326.
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FORMULA
| Number triangle T(n,k)=sum{j=0..n-k, C(n-j,k)*C(2k,j)}.
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EXAMPLE
| 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
| Sequence in context: A119673 A144447 A051455 * A141541 A177947 A132789
Adjacent sequences: A158684 A158685 A158686 * A158688 A158689 A158690
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Mar 24 2009
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