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A075177
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Indices of additive primes - primes with prime sum-of-digits, see A046704.
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6
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1, 2, 3, 4, 5, 9, 10, 13, 14, 15, 18, 19, 23, 24, 26, 30, 32, 33, 34, 36, 37, 40, 41, 43, 44, 45, 46, 48, 49, 50, 53, 56, 57, 60, 61, 64, 65, 66, 67, 68, 71, 72, 74, 75, 78, 79, 80, 82, 86, 87, 89, 90, 91, 93, 102, 105, 106, 108, 109, 110, 111, 116, 117, 118, 121, 124, 128
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OFFSET
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1,2
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COMMENTS
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There are 107 additive primes among first 200 primes. There are 38455 additive primes among first 100000 primes. Additive primes are in A046704.
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LINKS
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FORMULA
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EXAMPLE
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Prime(10)=29 is additive prime because 2+9=11 is prime.
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MATHEMATICA
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Map[PrimePi[ # ]&, Select[Prime[Range[200]], PrimeQ[Apply[ Plus, IntegerDigits[ # ]]]&]
Flatten[Position[Prime[Range[150]], _?(PrimeQ[Total[IntegerDigits[#]]]&), {1}, Heads->False]] (* Harvey P. Dale, May 29 2013 *)
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PROG
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(Haskell)
import Data.List (elemIndices)
a075177 n = a075177_list !! (n-1)
a075177_list = map (+ 1) $
elemIndices 1 $ map (a010051 . a007953) a000040_list
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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