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A107987
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Odd composite numbers of the form p+2 where p is prime.
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1
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9, 15, 21, 25, 33, 39, 45, 49, 55, 63, 69, 75, 81, 85, 91, 99, 105, 111, 115, 129, 133, 141, 153, 159, 165, 169, 175, 183, 195, 201, 213, 225, 231, 235, 243, 253, 259, 265, 273, 279, 285, 295, 309, 315, 319, 333, 339, 351, 355, 361, 369, 375, 381, 385, 391, 399
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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DeleteCases[Prime[Range[2, 80]]+2, _?PrimeQ] (* Harvey P. Dale, Aug 15 2013 *)
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PROG
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(PARI) sum2pr(n) = \Composite numbers of form p+2. { c=0; cp=0; forprime(x=2, n, cp++; y=x+2; if(isprime(y)==0, c++; print1(y", ") ) ); print(); print(c/cp+.) }
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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