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Search: id:A166158
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| A166158 |
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Numbers n such that phi(n)+ number of perfect partitions of (n-1) = prime. |
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1
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| 1, 2, 3, 5, 6, 7, 10, 11, 13, 15, 17, 19, 22, 23, 29, 31, 33, 34, 37, 41, 43, 47, 53, 55, 58, 59, 61, 67, 69, 70, 71, 73, 78, 79, 82, 83, 85, 87, 89, 97, 101, 103, 105, 107, 109, 110, 113, 118, 123, 127, 130, 131, 137, 139, 142, 149, 151, 154, 157, 159, 163, 167, 173, 179
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Or, numbers n such that A000010(n)+A002033(n-1)=prime.
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EXAMPLE
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If n=1 and phi(1)+A002033(0)=1+1=2(prime), then a(1)=1.
If n=2 and phi(2)+A002033(1)=1+1=2(prime), then a(2)=2.
If n=3 and phi(3)+A002033(2)=2+1=3(prime), then a(3)=3.
If n=4, then phi(4)+A002033(3)=2+2=4=nonprime. If n=5 and phi(5)+A002033(4)=4+1=5(prime), then a(4)=5.
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CROSSREFS
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Cf. A000010, A000027, A000040, A002033.
Sequence in context: A144147 A068422 A085118 this_sequence A137313 A117204 A028805
Adjacent sequences: A166155 A166156 A166157 this_sequence A166159 A166160 A166161
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KEYWORD
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nonn
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 08 2009
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EXTENSIONS
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Index in the definition corrected, and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 10 2009
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