A231903 Even numbers which are the sum of two different primes > 3 in exactly one way.

12, 16, 20, 22, 26, 32, 38, 62

Offset: 1

Author

Pierre CAMI, Nov 15 2013

Keywords

• nonn

Comments

Conjecture: there are no more numbers > 62 in the sequence.

Remark that the two primes are one of a twin primes pair and a pair of twin primes for 12=5+7.

The pairs of primes are : 12=5+7, 16=5+11, 20=7+13, 22=5+17, 26=7+19, 32=13+19, 38=7+31, 62=19+43.

Examples

			10=3+7=5+5 not in the sequence (not >3 or not different),
12=5+7, 12 first in the sequence,
14=3+11=7+7 not in the sequence.
		

Crossrefs

Cf. A007534

Programs

PARI

is_A231903(n)={my(s=0);forprime(p=5,n\2-1,isprime(n-p)&&s++>1&&return);s} \\ - M. F. Hasler, Nov 22 2013

Extensions

Missing term a(7)=38 added by M. F. Hasler, Nov 22 2013