OFFSET
1,1
COMMENTS
Primes p such that 2*p+7, 4*p+21, 8*p+49 and 16*p+105 are also primes. - Vincenzo Librandi, Aug 04 2010
LINKS
John Cerkan, Table of n, a(n) for n = 1..10000
FORMULA
a(n) == 3 (mod 10). - John Cerkan, Oct 04 2016
MATHEMATICA
rp4Q[n_]:=AllTrue[Rest[NestList[2#+7&, n, 4]], PrimeQ]; Select[Prime[Range[ 50000]], rp4Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 30 2020 *)
PROG
(Magma) [n: n in [1..1000000] | IsPrime(n) and IsPrime(2*n+7) and IsPrime(4*n+21) and IsPrime(8*n+49) and IsPrime(16*n+105)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved