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A124234
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Riordan array (1/(1-x), x(1+x)^2).
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1
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1, 1, 1, 1, 3, 1, 1, 4, 5, 1, 1, 4, 11, 7, 1, 1, 4, 15, 22, 9, 1, 1, 4, 16, 42, 37, 11, 1, 1, 4, 16, 57, 93, 56, 13, 1, 1, 4, 16, 63, 163, 176, 79, 15, 1, 1, 4, 16, 64, 219, 386, 299, 106, 17, 1, 1, 4, 16, 64, 247, 638, 794, 470, 137, 19, 1
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graph;
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history;
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OFFSET
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0,5
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COMMENTS
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LINKS
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FORMULA
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T(n,k) = Sum_{j=0..n-k} C(2k,j).
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EXAMPLE
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Triangle begins
1,
1, 1,
1, 3, 1,
1, 4, 5, 1,
1, 4, 11, 7, 1,
1, 4, 15, 22, 9, 1,
1, 4, 16, 42, 37, 11, 1
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PROG
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(PARI) tabl(nn) = for (n=0, nn, for (k=0, n, print1(sum(j=0, n-k, binomial(2*k, j)), ", ")); print(); ); \\ Michel Marcus, Nov 05 2016
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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