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A096787
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Primes of form 4n+3 that are the sum of two consecutive composite numbers.
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13
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19, 31, 43, 67, 71, 79, 103, 127, 131, 139, 151, 163, 191, 199, 211, 223, 239, 251, 271, 283, 307, 311, 331, 367, 379, 419, 431, 439, 443, 463, 487, 491, 499, 523, 547, 571, 599, 607, 619, 631, 643, 647, 659, 683, 691, 727, 739, 743, 751, 787, 811, 823, 827
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OFFSET
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1,1
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LINKS
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FORMULA
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MATHEMATICA
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2Select[ Range[ 450], PrimeQ[ # ] == PrimeQ[ # + 1] == False && PrimeQ[2# + 1, GaussianIntegers -> True] == True &] + 1 (* Robert G. Wilson v, Jul 11 2004 *)
Select[Total/@Partition[Select[Range[500], CompositeQ], 2, 1], PrimeQ[#] && IntegerQ[ (#-3)/4]&] (* Harvey P. Dale, Mar 06 2019 *)
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PROG
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(PARI) nextcomposite(k)=if(k<3, 4, if(isprime(k), k+1, k));
{m=440; n=4; while(n<m, k=nextcomposite(n+1); p=n+k; if(isprime(p)&&(p%4)==3, print1(p, ", ")); n=k)} \\ Klaus Brockhaus, Jul 10 2004
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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