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A256451 Numbers n such that 10^n + prime(n) is prime. 0
2, 4, 27, 63, 756, 899, 8088, 15216, 47969, 50943 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(11) > 10^5. - Robert Price, Mar 29 2015

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

4 is in this sequence since the fourth prime is 7 and 10^4+7=10007 is prime.

MATHEMATICA

Select[Range[100000], PrimeQ[10^# + Prime[#]] &]

PROG

(PARI) for(n=1, 10^3, if(ispseudoprime(10^n+prime(n)), print1(n, ", "))) \\ Derek Orr, Mar 29 2015

(MAGMA) [n: n in [1..770] | IsPrime(NthPrime(n) + 10^n)]; // Vincenzo Librandi, Mar 30 2015

CROSSREFS

Cf. A110065, A110066, A110067.

Sequence in context: A104465 A175759 A098515 * A059719 A264930 A226347

Adjacent sequences:  A256448 A256449 A256450 * A256452 A256453 A256454

KEYWORD

nonn,hard,more

AUTHOR

Robert Price, Mar 29 2015

STATUS

approved

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Last modified December 15 04:23 EST 2019. Contains 329991 sequences. (Running on oeis4.)