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Search: id:A117708
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| A117708 |
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Numbers that are both lucky numbers and Chen primes. |
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+0
1
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| 3, 7, 13, 31, 37, 67, 127, 211, 307, 409, 487, 541, 577, 631, 769, 787, 937, 991, 1009, 1039, 1117, 1201, 1291, 1459, 1471, 1567, 1777, 1801, 2251, 2281, 2467, 2557, 2647, 2971, 3037, 3187, 3259, 3307, 3559, 3709, 3847, 3889, 4441, 4567, 4801, 4969, 4987
(list; graph; listen)
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OFFSET
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1,1
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MATHEMATICA
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lst = Range[1, 5000, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; chenQ[n_] := PrimeQ[n] && Plus @@ Last /@ FactorInteger[n + 2] < 3; Select[lst, chenQ@# &] - Robert G. Wilson v (rgwv(at)rgwv.com), May 12 2006
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CROSSREFS
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Cf. A031157, A109611.
Cf. A031157, A109611.
Sequence in context: A136051 A100750 A105435 this_sequence A093431 A083520 A162869
Adjacent sequences: A117705 A117706 A117707 this_sequence A117709 A117710 A117711
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KEYWORD
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nonn
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AUTHOR
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Jani Melik (jani_melik(AT)hotmail.com), Apr 27 2006
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EXTENSIONS
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Corrected and extended by Robert G. Wilson v (rgwv(at)rgwv.com), May 12 2006
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