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Search: id:A108296
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| A108296 |
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Diagonal sums of the number triangle associated to A086617. |
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+0
3
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| 1, 1, 2, 3, 5, 8, 14, 24, 43, 78, 144, 269, 509, 971, 1868, 3618, 7049, 13805, 27162, 53661, 106405, 211697, 422458, 845386, 1696017, 3410522, 6873060, 13878721, 28077439, 56900936, 115501012, 234807488, 478032437, 974507543, 1989123814
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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The triangle associated to A086617 is given by T(n,k)=if(k<=n, sum{j=0..n-k, C(n-k,j)C(k,j)C(j)},0). A050253(n)=A108296(n+2)-A108296(n).
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FORMULA
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G.f.: (1-x^2-sqrt(1-2x^2-4x^3-3x^4))/(2*x^3(1-x^2)); a(n)=sum{k=0..floor(n/2), sum{j=0..n-2k, C(n-2k, j)C(k, j)C(j)}.
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CROSSREFS
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Sequence in context: A038495 A079500 A007059 this_sequence A072100 A104882 A091956
Adjacent sequences: A108293 A108294 A108295 this_sequence A108297 A108298 A108299
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), May 31 2005
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