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Search: id:A117458
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| A117458 |
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Primes and their indices such that when their respective SOD's are both prime, the SOD of the index is the nextprime of the prime SOD. |
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+0
6
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| 227, 313, 1723, 2003, 2311, 2609, 3329, 3701, 4007, 4027, 4801, 4931, 5107, 7253, 10457, 12143, 12163, 12211, 12433, 12547, 13063, 14143, 14341, 14831, 15139, 15373, 16091, 17027, 17047, 19403, 20047, 20261, 21059, 21149, 22157, 23053
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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"SOD" = "sum of digits".
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FORMULA
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Individually sum the digits of both prime index and associated prime. If both sums are prime, and the sum of the index is the next prime of the prime SOD, add to sequence.
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EXAMPLE
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In a(1) = 313, the number 65 is the index of the prime 313. The SOD(i) = 11. The SOD(p) = 7. 11 is the next prime after 7.
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CROSSREFS
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Cf. A117459-A117463.
Sequence in context: A031513 A078765 A142261 this_sequence A142842 A142545 A088788
Adjacent sequences: A117455 A117456 A117457 this_sequence A117459 A117460 A117461
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KEYWORD
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easy,nonn,base
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Mar 18 2006
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