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A096788
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Numbers n such that both n and n+1 are composite numbers that add up to a prime of the form 4k+3.
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10
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9, 15, 21, 33, 35, 39, 51, 63, 65, 69, 75, 81, 95, 99, 105, 111, 119, 125, 135, 141, 153, 155, 165, 183, 189, 209, 215, 219, 221, 231, 243, 245, 249, 261, 273, 285, 299, 303, 309, 315, 321, 323, 329, 341, 345, 363, 369, 371, 375, 393, 405, 411, 413, 429, 441
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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MATHEMATICA
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Select[ Range[ 450], PrimeQ[ # ] == PrimeQ[ # + 1] == False && PrimeQ[2# + 1, GaussianIntegers -> True] == True &] (* Robert G. Wilson v, Jul 11 2004 *)
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PROG
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(PARI) nextcomposite(k)=if(k<3, 4, if(isprime(k), k+1, k));
{m=455; n=4; while(n<m, k=nextcomposite(n+1); p=n+k; if(isprime(p)&&(p%4)==3, print1(n, ", ")); n=k)} \\ Klaus Brockhaus, Jul 10 2004
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CROSSREFS
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Subsequence (odd numbers) of A096784. See A096787 for the associated primes.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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Incorrect comment about Gaussian primes deleted by N. J. A. Sloane, Mar 02 2011
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STATUS
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approved
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