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A296192
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Denominators of the Harary index of the n X n grid graph.
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1
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1, 1, 6, 5, 28, 630, 396, 9009, 24024, 87516, 1511640, 5819814, 4576264, 106234700, 1147334760, 1890494775, 11031593040, 343817983080, 292314884400, 10274868186660
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OFFSET
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1,3
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LINKS
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EXAMPLE
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0, 5, 133/6, 293/5, 3399/28, 137111/630, 140351/396, ...
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MATHEMATICA
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Table[n (2 n + 1) (2 + (2 n - 1) Derivative[1][Log[CatalanNumber[# - 1]] &][n] - n)/3, {n, 20}] // FullSimplify // Denominator
Table[n (2 n + 1) (2 + (2 n - 1) (HarmonicNumber[n - 3/2] - HarmonicNumber[n] + 2 Log[2]) - n)/3, {n, 20}] // FunctionExpand // FullSimplify // Denominator
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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