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A099567
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Riordan array (1/(1-x-x^3),1/(1-x)).
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2
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1, 1, 1, 1, 2, 1, 2, 3, 3, 1, 3, 5, 6, 4, 1, 4, 8, 11, 10, 5, 1, 6, 12, 19, 21, 15, 6, 1, 9, 18, 31, 40, 36, 21, 7, 1, 13, 27, 49, 71, 76, 57, 28, 8, 1, 19, 40, 76, 120, 147, 133, 85, 36, 9, 1, 28, 59, 116, 196, 267, 280, 218, 121, 45, 10, 1, 41, 87, 175, 312, 463, 547, 498, 339
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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COMMENTS
| Inverse matrix is A099569. Row sums are A099568.
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FORMULA
| Number triangle T(n, k)=sum{j=0..n, binomial(n-2j, k+j)}; Columns have g.f. (1/(1-x-x^3))(x/(1-x))^k.
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EXAMPLE
| Rows begin {1}, {1,1}, {1,2,1}, {2,3,3,1}, {3,5,6,4,1},...
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CROSSREFS
| Sequence in context: A112531 A100002 A057041 * A140530 A202191 A052250
Adjacent sequences: A099564 A099565 A099566 * A099568 A099569 A099570
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Oct 22 2004
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