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A064409 Positive even numbers not of the form A001359(i) + A006512(j) for integers i and j. 2

%I #12 Feb 16 2024 14:44:29

%S 2,4,6,14,20,26,28,32,38,40,44,50,52,56,58,62,68,70,74,80,82,86,88,92,

%T 94,96,98,100,104,110,116,118,122,124,128,130,134,136,140,146,148,152,

%U 158,160,164,166,170,172,176,178,182,188,190,194,200

%N Positive even numbers not of the form A001359(i) + A006512(j) for integers i and j.

%C This is different from A007534, which gives positive even numbers which are not the same of a pair of twin primes. The old definition of the present sequence was misleading. - _N. J. A. Sloane_, Feb 16 2024

%H A.H.M. Smeets, <a href="/A064409/b064409.txt">Table of n, a(n) for n = 1..20177</a>

%e 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 current sequence because no combination of any two numbers from each set just enumerated can be summed to make 20.

%t 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} ] ] ] ]

%Y Cf. A001359, A006512, A007534.

%K nonn

%O 1,1

%A _Robert G. Wilson v_, Sep 29 2001

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Last modified April 25 12:27 EDT 2024. Contains 371969 sequences. (Running on oeis4.)