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A172015
Numbers of the form 6*k-+1 such that 6*k-1=prime and 6*k+1=nonprime.
2
23, 25, 47, 49, 53, 55, 83, 85, 89, 91, 113, 115, 131, 133, 167, 169, 173, 175, 233, 235, 251, 253, 257, 259, 263, 265, 293, 295, 317, 319, 353, 355, 359, 361, 383, 385, 389, 391, 401, 403, 443, 445, 449, 451, 467, 469, 479, 481, 491, 493, 503, 505, 509, 511
OFFSET
1,1
MATHEMATICA
Select[Table[{6k-1, 6k+1}, {k, 1, 100}], PrimeQ[ #[[1]] ] && !PrimeQ[ #[[2]] ]&] // Flatten (* Jean-François Alcover, Nov 24 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Entries checked by R. J. Mathar, Apr 14 2010
STATUS
approved