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Search: id:A142337
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| A142337 |
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If A024916(n) is prime: a(n)=If[PrimeQ[Sum[DivisorSigma[1, i], {i, 1, n}]], n, {}]. |
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+0
1
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| 7, 12, 18, 23, 24, 32, 49, 66, 84, 87, 90, 92, 111, 112, 113, 114, 129, 130, 132, 133, 137, 138, 199, 238, 239, 271, 275, 278, 283, 285
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n)=If[PrimeQ[Sum[DivisorSigma[1, i], {i, 1, n}]], n, {}].
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MATHEMATICA
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Flatten[Table[If[PrimeQ[Sum[DivisorSigma[1, i], {i, 1, n}]], n, {}], {n, 1, 300}]].
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CROSSREFS
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Cf. A024916.
Sequence in context: A091573 A092094 A064665 this_sequence A131912 A022953 A030714
Adjacent sequences: A142334 A142335 A142336 this_sequence A142338 A142339 A142340
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KEYWORD
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nonn,uned
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AUTHOR
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Roger L. Bagula and Gary W. Adamson (rlbagulatftn(AT)yahoo.com), Sep 18 2008
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