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A232725
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Numbers n such that the concatenation 123456789n is prime.
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1
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1, 23, 29, 49, 133, 143, 167, 191, 199, 217, 257, 311, 403, 409, 419, 433, 437, 451, 457, 473, 563, 587, 601, 623, 629, 653, 671, 689, 721, 761, 769, 779, 803, 809, 851, 871, 881, 893, 913, 943, 947, 959, 1003, 1013, 1027, 1069, 1079, 1091, 1153, 1163, 1177
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..51.
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EXAMPLE
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721 is a member of this sequence because 123456789721 is prime.
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PROG
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(Python)
from sympy import isprime
{print(n, end=', ') for n in range(2000) if isprime(int("123456789"+str(n)))}
# Simplified by Derek Orr, Apr 10 2015
(PARI) for(n=1, 2000, if(isprime(eval(concat("123456789", Str(n)))), print1(n, ", "))) \\ Derek Orr, Apr 10 2015
(Magma) [n: n in [0..1500] | IsPrime(Seqint(Intseq(n) cat Intseq(123456789)))]; // Vincenzo Librandi, Apr 11 2015
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CROSSREFS
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Cf. A232726, A104914, A104915.
Sequence in context: A102904 A108249 A338324 * A045120 A174260 A097436
Adjacent sequences: A232722 A232723 A232724 * A232726 A232727 A232728
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KEYWORD
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nonn,base
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AUTHOR
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Derek Orr, Nov 29 2013
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EXTENSIONS
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More terms from Derek Orr, Apr 10 2015
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STATUS
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approved
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