OFFSET
1,1
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..12638
EXAMPLE
a(1) = 7 is prime. 7 + 6^1 = 13, 7 + 6^2 = 43, 7 + 6^3 = 223 and 7 + 6^4 = 1303 are also prime. It is the smallest such set of 5 primes; (Quintet).
MATHEMATICA
Select[k = {1, 2, 3, 4}; Prime[Range[500]], And @@ PrimeQ[# + 6^k] &]
PROG
(PARI)
forprime(p=1, 10^4, c=1; for(k=1, 4, if(!isprime(p+6^k), c--; break)); if(c, print1(p, ", "))) \\ Derek Orr, Sep 20 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
K. D. Bajpai, Sep 20 2014
STATUS
approved