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Search: id:A064409
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| A064409 |
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Even numbers not the sum of a pair twin primes, one the lesser and the other the greater. |
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+0
1
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| 2, 4, 6, 14, 20, 26, 28, 32, 38, 40, 44, 50, 52, 56, 58, 62, 68, 70, 74, 80, 82, 86, 88, 92, 94, 96, 98, 100, 104, 110, 116, 118, 122, 124, 128, 130, 134, 136, 140, 146, 148, 152, 158, 160, 164, 166, 170, 172, 176, 178, 182, 188, 190, 194, 200
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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The lesser of the twin primes < 200 are 3, 5, 11, 17, 29, 41, 59, 71, 101, 107, 137, 149, 179, 191, 197 and the greater of the twin primes < 200 are 5, 7, 13, 19, 31, 43, 61, 73, 103, 109, 139, 151, 181, 193, 199. 20 is in the above sequence because no combination of any two numbers from each set just enumerated can be summed to make 20.
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MATHEMATICA
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p = Select[ Range[ 200 ], PrimeQ[ # ] && PrimeQ[ # + 2 ] & ]; q = p + 2; Complement[ Table[ n, {n, 2, 200, 2} ], Union[ Flatten[ Table[ p[ [ i ] ] + q[ [ j ] ], {i, 1, 15}, {j, 1, 15} ] ] ] ]
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CROSSREFS
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Adjacent sequences: A064406 A064407 A064408 this_sequence A064410 A064411 A064412
Sequence in context: A138307 A124693 A095698 this_sequence A032353 A062112 A084685
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 29 2001
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