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A025583
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Composite numbers that are not the sum of 2 primes.
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9
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27, 35, 51, 57, 65, 77, 87, 93, 95, 117, 119, 121, 123, 125, 135, 143, 145, 147, 155, 161, 171, 177, 185, 187, 189, 203, 205, 207, 209, 215, 217, 219, 221, 237, 245, 247, 249, 255, 261, 267, 275, 287, 289, 291, 297, 299, 301, 303, 305, 321, 323, 325, 327, 329, 335, 341
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Goldbach conjectured that every integer >5 is the sum of three primes.
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Index entries for sequences related to Goldbach conjecture
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MATHEMATICA
| f[n_] := (p = 0; pn = PrimePi[n]; Do[ If[n == Prime[i] + Prime[k], p = p + 1; If[p > 2, Break[]]], {i, 1, pn}, {k, i, pn}]; p ); Select[Range[2, 400], ! PrimeQ[#] && f[#] == 0 & ] (* Jean-François Alcover, Mar 07 2011 *)
upto=350; With[{c=PrimePi[upto]}, Complement[Range[4, upto], Prime[Range[ c]], Union[Total/@Tuples[Prime[Range[c]], {2}]]]] (* From Harvey P. Dale, Jul 14 2011 *)
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CROSSREFS
| Cf. A051034, A001031, A002372, A002374, A071335.
Sequence in context: A032584 A072492 A164376 * A134101 A098883 A160119
Adjacent sequences: A025580 A025581 A025582 * A025584 A025585 A025586
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KEYWORD
| nonn,nice,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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