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Search: id:A114123
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| A114123 |
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Riordan array (1/(1-x), x(1+x)^2/(1-x)^2). |
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+0
2
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| 1, 1, 1, 1, 5, 1, 1, 13, 9, 1, 1, 25, 41, 13, 1, 1, 41, 129, 85, 17, 1, 1, 61, 321, 377, 145, 21, 1, 1, 85, 681, 1289, 833, 221, 25, 1, 1, 113, 1289, 3653, 3649, 1561, 313, 29, 1, 1, 145, 2241, 8989, 13073, 8361, 2625, 421, 33, 1, 1, 181, 3649, 19825, 40081, 36365, 16641
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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Row sums are A099463(n+1). Diagonal sums are A116404.
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FORMULA
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Number triangle T(n,k)=sum{j=0..n, C(2k,n-k-j)*C(n-k,j)*2^(n-k-j)}
T(n,k)=sum{j=0..n-k, C(2k,j)C(n-k,j)*2^j};
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EXAMPLE
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Triangle begins
1,
1, 1,
1, 5, 1,
1, 13, 9, 1,
1, 25, 41, 13, 1,
1, 41, 129, 85, 17, 1,
1, 61, 321, 377, 145, 21, 1
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CROSSREFS
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Sequence in context: A110522 A146987 A130227 this_sequence A143007 A152654 A157177
Adjacent sequences: A114120 A114121 A114122 this_sequence A114124 A114125 A114126
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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), Feb 07 2006, Oct 22 2006
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