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Search: id:A118333
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| A118333 |
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Largest prime factor of n!! + (n+1)!!. |
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+0
2
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| 2, 3, 5, 11, 23, 7, 17, 163, 443, 29, 73, 251, 4027, 2477, 499, 199, 883, 47, 2671, 308333, 2099, 859, 510481, 10429, 514519, 29629, 51713, 42337, 5407, 13841, 151733, 2448023843, 3133033, 89101, 61613, 19448653009, 50136277, 63259211
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OFFSET
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0,1
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COMMENT
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First five terms coincide with A118332 because n!! + (n+1)!! is prime for n = 0, 1, 2, 3, 4. At n>4, n!! + (n+1)!! is always composite.
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MATHEMATICA
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Table[FactorInteger[n!!+(n+1)!! ][[ -1, 1]], {n, 0, 40}]
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CROSSREFS
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Cf. A118332.
Adjacent sequences: A118330 A118331 A118332 this_sequence A118334 A118335 A118336
Sequence in context: A073879 A073880 A118332 this_sequence A131101 A005384 A118571
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Apr 23 2006
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