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A302093
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a(n) = floor(C(n/2)*C(n/2+1)), where C = Catalan numbers (A000108).
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0
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1, 1, 2, 4, 10, 25, 70, 199, 588, 1784, 5544, 17569, 56628, 185202, 613470, 2054998, 6952660, 23732911, 81662152, 283026021, 987369656, 3465222945, 12228193432, 43369190282, 154532114800, 552998717472, 1986841476000, 7164993393905, 25928281261800, 94132464529902
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OFFSET
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0,3
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LINKS
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EXAMPLE
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k a(k) is prime
2 2
7 199
11 17569
17 23732911
81 102313363987695596246576033222404783284068513
619 200823128294216578246...307006792344011246479 (366 digits)
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MATHEMATICA
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Table[Floor[CatalanNumber[n/2] CatalanNumber[n/2 + 1]], {n, 0, 35}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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