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A087368
Prime-indexed primes (PIPs) whose digits are all primes.
2
3, 5, 277, 353, 773, 3733, 5557, 7523, 7753, 25357, 25733, 27733, 32233, 32323, 32533, 37273, 53233, 53353, 53377, 53777, 55733, 72337, 72727, 73757, 77377, 77557, 232523, 272333, 275773, 322727, 327553, 327757, 333233, 352357, 353527
OFFSET
1,1
COMMENTS
Chances are these numbers are infinite since PIPs are infinite.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..14683 (terms below 10^11)
Albert Frank and Philippe Jacqueroux, International Contest, 2001. Item 12.
EXAMPLE
59 is prime, the 59th prime is 277, and 2 and 7 are primes.
MATHEMATICA
Select[Flatten[Table[FromDigits /@ Tuples[Prime[Range[4]], k], {k, 1, 6}]], PrimeQ[#] && PrimeQ[PrimePi[#]] &] (* Amiram Eldar, Jul 08 2024 *)
PROG
(PARI) pip(n) = { for(x=1, n, flag=1; y=prime(prime(x)); y2=y; for(j=1, length(Str(y)), r = y%10; if(!isprime(r), flag=0); y = floor(y/10); ); if(flag, print1(y2", ")); ) }
CROSSREFS
Intersection of A006450 and A046034.
Sequence in context: A167483 A101331 A232239 * A309740 A280035 A087670
KEYWORD
easy,nonn,base
AUTHOR
Cino Hilliard, Oct 21 2003
EXTENSIONS
Offset corrected by Amiram Eldar, Jul 08 2024
STATUS
approved