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Search: id:A100118
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| A100118 |
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Numbers whose sum of prime factors is prime (counted with multiplicity). |
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+0
13
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| 2, 3, 5, 6, 7, 10, 11, 12, 13, 17, 19, 22, 23, 28, 29, 31, 34, 37, 40, 41, 43, 45, 47, 48, 52, 53, 54, 56, 58, 59, 61, 63, 67, 71, 73, 75, 76, 79, 80, 82, 83, 88, 89, 90, 96, 97, 99, 101, 103, 104, 107, 108, 109, 113, 117, 118, 127, 131, 136, 137, 139, 142, 147, 148, 149
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers n such that integer log of n is a prime number.
As in A001414, denote sopfr(n) the integer log of n. Since sopfr(p)=p, the sequence includes all prime numbers.
See A046363 for the analogue excluding prime numbers. - Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), Oct 20 2007
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EXAMPLE
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e.g. 40 = 2^3*5 and 2*3+5=11 is a prime number.
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MATHEMATICA
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L = {}; Do[ww = Transpose[FactorInteger[k]]; w = ww[[1]].ww[[2]]; If[PrimeQ[w], AppendTo[L, k]], {k, 2, 500}]; L
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CROSSREFS
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Cf. A001414.
Cf. A046363.
Sequence in context: A024899 A114518 A066940 this_sequence A028781 A136149 A101882
Adjacent sequences: A100115 A100116 A100117 this_sequence A100119 A100120 A100121
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KEYWORD
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easy,nonn
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AUTHOR
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Carlos Alves (cjsalves(AT)gmail.com), Dec 26 2004
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