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A232767
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Primes p such that the concatenation p987654321 is prime.
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2
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97, 107, 149, 179, 193, 233, 271, 359, 421, 439, 449, 457, 491, 499, 547, 557, 593, 673, 677, 701, 769, 821, 839, 947, 971, 1019, 1021, 1051, 1069, 1087, 1091, 1093, 1103, 1117, 1163, 1297, 1301, 1307, 1327, 1399, 1409, 1439, 1453, 1483, 1493, 1579, 1597, 1609
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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107 is a member of this sequence because 107 is prime and 107987654321 is prime.
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MATHEMATICA
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With[{r=Range[9, 1, -1]}, Select[Prime[Range[500]], PrimeQ[FromDigits[ Join[ IntegerDigits[#], r]]]&]] (* Harvey P. Dale, Jul 31 2014 *)
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PROG
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(Python)
from sympy import isprime
{print(n, end=', ') for n in range(10**4) if isprime(n) and isprime(int(str(n)+"987654321"))}
(PARI) forprime(p=1, 10^4, if(isprime(eval(concat(Str(p), "987654321"))), print1(p, ", "))) \\ Derek Orr, Apr 10 2015
(Magma) [NthPrime(n): n in [0..500] | IsPrime(Seqint(Intseq(987654321) cat Intseq(NthPrime(n))))]; // Vincenzo Librandi, Apr 11 2015
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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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