OFFSET
1,1
COMMENTS
Primes p such that 10*p+9, 100*p+99 and 1000*p+999 are also primes. - Vincenzo Librandi, Aug 04 2010
LINKS
John Cerkan, Table of n, a(n) for n = 1..10000
MATHEMATICA
nrp3Q[n_]:=AllTrue[Rest[NestList[10#+9&, n, 3]], PrimeQ]; Select[Prime[ Range[ 2100]], nrp3Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 12 2019 *)
PROG
(Magma) [n: n in [1..450000] | IsPrime(n) and IsPrime(10*n+9) and IsPrime(100*n+99) and IsPrime(1000*n+999)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved