A278785 - OEIS

%I #7 Nov 28 2016 10:30:17

%S 7,17,19,29,31,37,47,53,61,67,79,83,107,127,137,157,173,179,193,199,

%T 211,229,271,277,307,331,359,379,409,419,421,433,439,443,499,503,509,

%U 523,547,571,587,619,631,653,673,677,701,709,719,727,739,751,787,823

%N Primes p such that prime(p-2) + prime(p-1) + prime(p+1) is prime.

%H Harvey P. Dale, <a href="/A278785/b278785.txt">Table of n, a(n) for n = 1..1000</a>

%e 31 is a member because p(n-2)=23 plus p(n-1)=29 plus p(n+1)=37 equals 89 which is prime.

%t Select[Partition[Prime[Range[6000]],4,1],PrimeQ[First[#]+#[[2]]+ Last[ #]]&] [[All,3]]

%o (PARI) is(n)=if(n<7 || !isprime(n), return(0)); my(p=prime(n-2),q=nextprime(p+1)); isprime(nextprime(n+1)+p+q) \\ _Charles R Greathouse IV_, Nov 28 2016

%K nonn

%O 1,1

%A _Harvey P. Dale_, Nov 28 2016