A152470 Largest of three consecutive primes whose sum is a prime.

11, 13, 17, 23, 29, 31, 37, 41, 47, 61, 71, 73, 79, 89, 97, 107, 127, 151, 157, 167, 173, 211, 227, 239, 281, 293, 307, 311, 317, 349, 353, 359, 389, 401, 419, 421, 439, 461, 463, 479, 487, 503, 509, 523, 563, 631, 647, 661, 673, 677, 719, 733, 757, 761, 769

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Dec 05 2008

Keywords

• nonn

Examples

			3+5+7 = 15 is composite.
5+7+11 = 23 is prime and (5, 7, 11) are consecutive primes so a(1) = 11.
		

Links

• Pierre CAMI, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A073681, A072225, A152468, A152469.

Programs

Maple

Primes:= select(isprime,[2,(2*i+1 $ i=1..10000)]):
Primes[select(t -> isprime(Primes[t-2]+Primes[t-1]+Primes[t]),[$3..nops(Primes)])];
# Robert Israel, Aug 29 2014

Mathematica

lst={};Do[p0=Prime[n];p1=Prime[n+1];p2=Prime[n+2];If[PrimeQ[p0+p1+p2],AppendTo[lst,p2]],{n,6!}];lst

PARI

s=[]; for(n=1, 1000, if(isprime(prime(n)+prime(n+1)+prime(n+2)), s=concat(s, prime(n+2)))); s \\ Colin Barker, Aug 25 2014