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Search: id:A066038
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| A066038 |
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Numbers with at least two prime factors such that the sum of the prime factors is prime. |
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+0
1
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| 6, 10, 12, 18, 20, 22, 24, 34, 36, 40, 44, 48, 50, 54, 58, 68, 72, 80, 82, 88, 96, 100, 108, 116, 118, 136, 142, 144, 160, 162, 164, 165, 176, 192, 200, 202, 210, 214, 216, 232, 236, 242, 250, 272, 273, 274, 284, 288, 298, 320, 324, 328, 345, 352, 358, 382, 384
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers with just one prime factor trivially satisfy the defining condition and are nor included.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
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The prime factors of 12 are 2 and 3, which add up to 5, a prime.
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PROGRAM
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(PARI) sopf(n)= { local(f, s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) } { n=0; for (m=1, 10^9, if (omega(m) > 1 && isprime(sopf(m)), write("b066038.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 07 2009]
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CROSSREFS
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Sequence in context: A102148 A107407 A119689 this_sequence A125592 A110085 A114520
Adjacent sequences: A066035 A066036 A066037 this_sequence A066039 A066040 A066041
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KEYWORD
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nonn,new
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 12 2001
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 13 2001
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