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1, 1, 1, 2, 2, 1, 2, 4, 3, 1, 2, 6, 7, 4, 1, 2, 8, 13, 11, 5, 1, 2, 10, 21, 24, 16, 6, 1, 2, 12, 31, 45, 40, 22, 7, 1, 2, 14, 43, 76, 85, 62, 29, 8, 1, 2, 16, 57, 119, 161, 147, 91, 37, 9, 1, 2, 18, 73, 176, 280, 308, 238, 128, 46, 10, 1, 2, 20, 91, 249, 456
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graph;
refs;
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internal format)
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OFFSET
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0,4
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COMMENTS
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Riordan array ((1+x^2)/(1-x), x/(1-x)).
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LINKS
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FORMULA
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A129686 * A007318 (Pascal's Triangle), as infinite lower triangular matrices.
T(n,k) = T(n-1,k) + T(n-1,k-1), T(0,0) = T(1,0) = T(1,1) = T(2,2) = 1, T(2,0) = T(2,1) = 2, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Feb 12 2014
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EXAMPLE
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First few rows of the triangle:
1;
1, 1;
2, 2, 1;
2, 4, 3, 1;
2, 6, 7, 4, 1;
2, 8, 13, 11, 5, 1;
2, 10, 21, 24, 16, 6, 1;
2, 12, 31, 45, 40, 22, 7, 1;
2, 14, 43, 76, 85, 62, 29, 8, 1;
2, 16, 57, 119, 161, 147, 91, 37, 9, 1;
...
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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