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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
OFFSET
1,1
COMMENTS
a(11) > 10^5. - Robert Price, Mar 29 2015
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
KEYWORD
nonn,hard,more
AUTHOR
Robert Price, Mar 29 2015
STATUS
approved