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

1,1

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.

Links

Table of n, a(n) for n=1..8.

Example

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.

Prog

(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

Crossrefs

Cf. A007534

Sequence in context: A171955 A225071 A210577 * A364405 A337703 A337700

Adjacent sequences: A231900 A231901 A231902 * A231904 A231905 A231906

Keyword

nonn

Author

Pierre CAMI, Nov 15 2013

Extensions

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

Status

approved