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Search: id:A055632
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| A055632 |
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Sum of totient function of primes dividing n is a prime. |
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+0
3
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| 3, 6, 9, 10, 12, 14, 18, 20, 22, 24, 26, 27, 28, 30, 34, 36, 38, 40, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 66, 68, 70, 72, 74, 76, 80, 81, 82, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 112, 116, 118, 120, 122, 124, 130, 132, 134, 136, 140, 142, 144, 146
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Observe that this sequence includes even numbers and for all primes p as (a phi-sum) an infinite number of solutions exist, like e.g. (2^w)*p, with 1+p-1=p Phi-sum over its factors.
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EXAMPLE
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If n=2^a*3^b*5^c*7^d*11^e then prime-factor set is {2,3,5,7,11}. The totient function values of this set are {1,2,4,6,10} and the sum is 1+2+4+6+10=23.
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CROSSREFS
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A001221, A006093, A053571, A055631.
Sequence in context: A081605 A110263 A022304 this_sequence A133006 A055264 A113502
Adjacent sequences: A055629 A055630 A055631 this_sequence A055633 A055634 A055635
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jun 06 2000
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