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Search: id:A114522
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| A114522 |
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Numbers n such that sum of distinct prime divisors of n is prime. |
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+0
6
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| 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16, 17, 18, 19, 20, 22, 23, 24, 25, 27, 29, 31, 32, 34, 36, 37, 40, 41, 43, 44, 47, 48, 49, 50, 53, 54, 58, 59, 61, 64, 67, 68, 71, 72, 73, 79, 80, 81, 82, 83, 88, 89, 96, 97, 100, 101, 103, 107, 108, 109, 113, 116, 118, 121, 125, 127
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence is the union of the primes and sequence A047820.
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EXAMPLE
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24 = 2^3 * 3, and 2 + 3 = 5, which is prime. So 24 is included.
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MATHEMATICA
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f[n_] := Plus @@ First /@ FactorInteger[n]; Select[Range[130], PrimeQ[f[ # ]] &] (*Chandler*)
Select[Range@127, PrimeQ[Plus @@ First /@ FactorInteger@# ] &] (* Robert G. Wilson v *)
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PROGRAM
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(PARI) for(n=1, 200, v=factor(n); s=0; for(i=1, matsize(v)[1], s+=v[i, 1]); if(isprime(s), print1(n, ", "))) (Herrgesell)
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CROSSREFS
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Cf. A114518, A047820, A008472.
Sequence in context: A048338 A102450 A023782 this_sequence A053432 A106039 A108897
Adjacent sequences: A114519 A114520 A114521 this_sequence A114523 A114524 A114525
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 05 2005
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EXTENSIONS
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Extended by Robert G. Wilson v (rgwv(at)rgwv.com), Ray Chandler (rayjchandler(AT)sbcglobal.net) and Lambert Herrgesell (zero815(AT)googlemail.com), Dec 07 2005
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