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A231903 Even numbers which are the sum of two different primes > 3 in exactly one way. 0
12, 16, 20, 22, 26, 32, 38, 62 (list; graph; refs; listen; history; text; internal format)
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 * A243538 A183052 A240052

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

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Last modified May 19 20:41 EDT 2019. Contains 323410 sequences. (Running on oeis4.)