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A109981
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Primes such that both the sum of digits and the number of digits are primes.
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3
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11, 23, 29, 41, 43, 47, 61, 67, 83, 89, 101, 113, 131, 137, 139, 151, 157, 173, 179, 191, 193, 197, 199, 223, 227, 229, 241, 263, 269, 281, 283, 311, 313, 317, 331, 337, 353, 359, 373, 379, 397, 401, 409, 421, 443, 449, 461, 463, 467, 487, 557, 571, 577, 593
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OFFSET
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1,1
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COMMENTS
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Cf. A046704 Additive primes: sum of digits is a prime, A088136 Primes such that sum of first and last digits is prime.
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LINKS
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EXAMPLE
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a(86) = 10037 because both the sum (=11) and number (=5) of digits are primes.
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MATHEMATICA
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Select[Prime[Range[200]], PrimeQ[Length[IntegerDigits[ # ]]]&&PrimeQ[Plus@@IntegerDigits[ # ]]&]
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PROG
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(Haskell)
a109981 n = a109981_list !! (n-1)
a109981_list = filter ((== 1) . a010051' . a055642) a046704_list
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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