

A134650


Numbers n such that n is the sum of two consecutive primes (i.e., in A001043) but is not the sum of two sums of two consecutive primes.


2




OFFSET

1,1


COMMENTS

Numbers in A001043 but not in A134651.
Conjectured to be finite, may be complete.
a(8), if it exists, is greater than 20100000.  R. J. Mathar, Jan 26 2008


REFERENCES

R. K. Guy, ed., Unsolved Problems, Western Number Theory Meeting, Las Vegas, 1988.


LINKS

Table of n, a(n) for n=1..7.


MAPLE

with(numtheory): Sset := {}: for i to 15000 do Sset := `union`(Sset, {ithprime(i) + ithprime(i + 1)}) od: Sset := convert(Sset, list): for n from 1 to nops(Sset) do count := 0: s := Sset[n]: for i from 1 to n do if member(s  Sset[i], Sset) and sSset[i] >= s/2 then count := count + 1 fi; od: if count = 0 then printf(`%d, `, Sset[n]) fi; od: # James A. Sellers, Jan 28 2008


CROSSREFS

Cf. A001043, A134651, A135045.
Sequence in context: A020749 A120135 A162704 * A314412 A314413 A314414
Adjacent sequences: A134647 A134648 A134649 * A134651 A134652 A134653


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane, Jan 25 2008


EXTENSIONS

946 found by James A. Sellers, Jan 25 2008


STATUS

approved



