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Search: id:A144657
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| A144657 |
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a(n) = Sum[Sum[(i+j)!/(i!*j!),{i,1,n}],{j,1,n}]. |
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+0
2
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| 0, 2, 14, 62, 242, 912, 3418, 12854, 48602, 184736, 705410, 2704132, 10400574, 40116572, 155117490, 601080358, 2333606186, 9075135264, 35345263762, 137846528780, 538257874398, 2104098963676, 8233430727554
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OFFSET
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0,2
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MATHEMATICA
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Table[Sum[Sum[(i+j)!/i!/j!/2, {i, 1, n}], {j, 1, n}], {n, 1, 20}]
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CROSSREFS
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Suggested by a formula in A048775.
Sequence in context: A058738 A095376 A153332 this_sequence A167555 A109869 A084132
Adjacent sequences: A144654 A144655 A144656 this_sequence A144658 A144659 A144660
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jan 30 2009
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