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Search: id:A124279
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| A124279 |
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Riordan array (1/(1-x),x(1-x+x^2)/(1-x)). |
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+0
3
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| 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 3, 1, 1, 1, 4, 5, 4, 1, 1, 1, 5, 8, 7, 5, 1, 1, 1, 6, 12, 13, 9, 6, 1, 1, 1, 7, 17, 22, 19, 11, 7, 1, 1, 1, 8, 23, 35, 35, 26, 13, 8, 1, 1, 1, 9, 30, 53
(list; table; graph; listen)
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OFFSET
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0,8
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COMMENT
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Row sums are A005314. Diagonal sums are A124280. T(2n,n) is A002426.
Reversal of A124445. - Paul Barry (pbarry(AT)wit.ie), Nov 01 2006
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FORMULA
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Number triangle T(n,k)=sum{j=0..n-k, C(j,n-k-j)C(k,n-k-j)}
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EXAMPLE
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Triangle begins
1,
1, 1,
1, 1, 1,
1, 2, 1, 1,
1, 3, 3, 1, 1,
1, 4, 5, 4, 1, 1,
1, 5, 8, 7, 5, 1, 1
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CROSSREFS
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Adjacent sequences: A124276 A124277 A124278 this_sequence A124280 A124281 A124282
Sequence in context: A136043 A096815 A124445 this_sequence A135225 A047030 A047120
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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), Oct 24 2006
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