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A232767 Primes p such that the concatenation p987654321 is prime. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes in A232766.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

107 is a member of this sequence because 107 is prime and 107987654321 is prime.

MATHEMATICA

With[{r=Range[9, 1, -1]}, Select[Prime[Range[500]], PrimeQ[FromDigits[ Join[ IntegerDigits[#], r]]]&]] (* Harvey P. Dale, Jul 31 2014 *)

PROG

(Python)

from sympy import isprime

{print(n, end=', ') for n in range(10**4) if isprime(n) and isprime(int(str(n)+"987654321"))}

# Simplified by Derek Orr, Apr 10 2015

(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

CROSSREFS

Cf. A232766, A104914, A104915.

Sequence in context: A033208 A274122 A095603 * A039490 A033202 A160032

Adjacent sequences:  A232764 A232765 A232766 * A232768 A232769 A232770

KEYWORD

nonn,base

AUTHOR

Derek Orr, Nov 29 2013

STATUS

approved

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Last modified March 19 04:17 EDT 2019. Contains 321311 sequences. (Running on oeis4.)