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A166501 Primes p such that (p reversed)+4 is also a prime. 5
3, 7, 31, 73, 79, 97, 313, 331, 349, 379, 397, 541, 571, 709, 739, 757, 769, 937, 967, 3037, 3061, 3067, 3121, 3163, 3187, 3217, 3229, 3253, 3313, 3319, 3361, 3433, 3457, 3529, 3547, 3613, 3631, 3643, 3673, 3739, 3769, 3847, 3889, 5011, 5023, 5101, 5107 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
{p = A000040(i): A004087(i)+4 in A000040}. - R. J. Mathar, Oct 16 2009
EXAMPLE
73 is in the sequence because 37+4=41 prime.
331 is in the sequence because 133+4=137 prime.
3457 is in the sequence because 7543+4=7547 prime.
MATHEMATICA
Select[Prime[Range[700]], PrimeQ[FromDigits[Reverse[IntegerDigits[#]]]+ 4]&] (* Harvey P. Dale, May 21 2012 *)
Select[Prime[Range[700]], PrimeQ[IntegerReverse[#]+4]&] (* Harvey P. Dale, Mar 16 2023 *)
PROG
(Magma) [p: p in PrimesUpTo(6000) | IsPrime(q+4) where q is Seqint(Reverse(Intseq(p)))]; // Vincenzo Librandi, Sep 15 2013
CROSSREFS
Sequence in context: A109140 A088193 A091383 * A261862 A226216 A244114
KEYWORD
nonn,base,less
AUTHOR
Vincenzo Librandi, Oct 15 2009
EXTENSIONS
Keyword:base added, 3163 inserted, sequence extended by R. J. Mathar, Oct 16 2009
STATUS
approved

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Last modified May 26 20:29 EDT 2024. Contains 372844 sequences. (Running on oeis4.)