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Search: id:A134650
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| A134650 |
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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. |
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+0
3
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OFFSET
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1,1
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COMMENT
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Numbers in A001043 but not in A134651.
Conjectured to be finite, may be complete.
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REFERENCES
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R. K. Guy, ed., Unsolved Problems, Western Number Theory Meeting, Las Vegas, 1988.
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MAPLE
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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 s-Sset[i] >= s/2 then count := count + 1 fi; od: if count = 0 then printf(`%d, `, Sset[n]) fi; od: - James A. Sellers (sellersj(AT)math.psu.edu), Jan 28 2008
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CROSSREFS
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Cf. A001043, A134651, A135045.
Adjacent sequences: A134647 A134648 A134649 this_sequence A134651 A134652 A134653
Sequence in context: A025001 A020749 A120135 this_sequence A134205 A134208 A115072
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KEYWORD
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nonn,fini,more
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AUTHOR
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njas, Jan 25 2008
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EXTENSIONS
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946 found by James A. Sellers (sellersj(AT)math.psu.edu), Jan 25 2008
a(8), if it exists, is greater than 20100000. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 26 2008
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