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A064408
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Even numbers not the sum of a pair of the greater of the twin primes.
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1
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2, 4, 6, 8, 16, 22, 28, 30, 34, 40, 42, 46, 52, 54, 58, 60, 64, 70, 72, 76, 82, 84, 88, 90, 94, 96, 98, 100, 102, 106, 112, 118, 120, 124, 126, 130, 132, 136, 138, 142, 148, 150, 154, 160, 162, 166, 168, 172, 174, 178, 180, 184, 190, 192, 196
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OFFSET
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1,1
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LINKS
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EXAMPLE
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The greater of the twin primes < 200 are 5, 7, 13, 19, 31, 43, 61, 73, 103, 109, 139, 151, 181, 193, 199. 22 is in the above sequence because no combination of any two numbers from the set just enumerated can be summed to make 22.
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MAPLE
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N:= 300: # to get all terms <= N
T:= select(t -> isprime(t) and isprime(t-2), {5, seq(6*i+1, i=1..N/6)}):
A:= {seq(i, i=2..N, 2)} minus {seq(seq(T[i]+T[j], j=1..i), i=1..nops(T))}:
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MATHEMATICA
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q = Select[ Range[ 200 ], PrimeQ[ # - 2 ] && PrimeQ[ #2 ] & ]; Complement[ Table[ n, {n, 2, 200, 2} ], Union[ Flatten[ Table[ q[ [ i ] ] + q[ [ j ] ], {i, 1, Length[ q ] }, {j, 1, i} ] ] ] ]
upto=200; Module[{gtp=Transpose[Select[Partition[Prime[Range[PrimePi[ upto]]], 2, 1], #[[2]]-#[[1]]==2&]][[2]]}, Complement[Range[2, upto, 2], Total/@ Tuples[gtp, 2]]] (* Harvey P. Dale, Jan 17 2015 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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