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 A232727 Numbers n such that the concatenation n123456789 is prime. 1
 28, 32, 41, 55, 56, 59, 74, 95, 100, 116, 119, 122, 124, 142, 154, 161, 164, 179, 184, 193, 200, 215, 217, 220, 230, 241, 259, 265, 278, 296, 298, 314, 332, 382, 392, 406, 409, 416, 424, 425, 439, 452, 455, 458, 460, 466, 475, 493, 496, 514, 515, 530, 536, 559, 572, 574, 598, 602, 613, 629, 634 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n in the primes of the form n987654321 are listed in A232766. Primes in sequence are in A232728. LINKS EXAMPLE 278 is a member of this sequence because 278123456789 is prime. MATHEMATICA Select[Range[700], PrimeQ[FromDigits[Flatten[{IntegerDigits[#], IntegerDigits[123456789]}]]] &] (* Vincenzo Librandi, Apr 28 2015 *) PROG (Python) from sympy import isprime {print(n, end=', ') for n in range(1, 10**3) if isprime(int(str(n)+'123456789'))} ## Simplified by Derek Orr, Apr 28 2015 (PARI) for(n=1, 10^3, if(isprime(eval(concat(Str(n), "123456789"))), print1(n, ", "))) \\ Derek Orr, Apr 28 2015 (MAGMA) [n: n in [0..700] | IsPrime(Seqint([9..1 by -1] cat Intseq(n)))]; // Vincenzo Librandi, Apr 28 2015 (Sage) [n for n in (1..700) if is_prime(n*10^9+123456789)] # Bruno Berselli, Apr 28 2015 CROSSREFS Cf. A104914, A104915, A232728, A232766. Sequence in context: A057483 A025367 A121018 * A232766 A230855 A090637 Adjacent sequences:  A232724 A232725 A232726 * A232728 A232729 A232730 KEYWORD nonn,base,easy AUTHOR Derek Orr, Nov 29 2013 EXTENSIONS More terms from Derek Orr, Apr 28 2015 STATUS approved

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Last modified April 26 08:04 EDT 2019. Contains 322472 sequences. (Running on oeis4.)