A232727 Numbers n such that the concatenation n123456789 is prime.

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

Offset

1,1

Comments

Numbers n in the primes of the form n987654321 are listed in A232766. Primes in sequence are in A232728.

Links

Table of n, a(n) for n=1..61.

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