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A181507
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Primes such that the sum of squares of digits of all primes up to itself is a prime.
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2
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3, 11, 17, 37, 43, 151, 173, 191, 223, 233, 367, 401, 421, 433, 449, 457, 509, 787, 839, 1019, 1061, 1103, 1123, 1171, 1187, 1217, 1237, 1451, 1663, 1709, 1723, 1871, 1901, 1973, 2251, 2297, 2351, 2371, 2753, 3023, 3121, 3181, 3217, 3221, 3319, 3389, 3391
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OFFSET
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1,1
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COMMENTS
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There are infinite twins: (3389,3391)-(8231,8233)-(18251,18253)-(23687,23689)-(26111,26113) .....
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LINKS
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FORMULA
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A linear approximation for the sequence is a(n)=128.81n-3291.7
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EXAMPLE
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a(5)=43 since sum of square of digits (2,3,5,7,...primes up to 43)=439 which is prime.
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MATHEMATICA
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Prime/@Flatten[Position[Accumulate[Total/@(IntegerDigits[Prime[Range[ 500]]]^2)], _?PrimeQ]] (* Harvey P. Dale, May 24 2012 *)
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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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