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A059511
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Main diagonal of the array A059217.
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1
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1, 3, 26, 471, 13953, 627421, 39873948, 3406344237, 376591685322, 52319828460127, 8922977163384085, 1832831375530080986, 446306812127457163805, 127130280682997045232005, 41881054710966221044222595, 15800074329058136531647698779
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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t[0, 0] = 1; t[0, _?EvenQ] = 1; t[_?OddQ, 0] = 1; t[n_, k_] /; OddQ[n + k](*up*):= t[n, k] = t[n + 1, k - 1] + Sum[t[n, j], {j, 0, k - 1}];
t[n_, k_] /; EvenQ[n + k](*down*):= t[n, k] = t[n - 1, k + 1] + Sum[t[j, k], {j, 0, n - 1}]; Table[t[n, n], {n, 0, 50}] (* G. C. Greubel, Sep 10 2017 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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