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A032621
Numbers k such that k concatenated with k+6 is a prime.
3
1, 11, 13, 17, 25, 31, 35, 43, 65, 71, 83, 95, 97, 101, 125, 127, 137, 151, 155, 157, 161, 163, 167, 187, 197, 203, 205, 211, 217, 221, 223, 227, 233, 235, 245, 251, 257, 263, 265, 271, 283, 317, 331, 335, 337, 341, 353, 355, 373, 385, 391, 401, 427, 433
OFFSET
1,2
MATHEMATICA
Select[Range[1, 501, 2], PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ #+6]]]]&] (* Harvey P. Dale, Nov 17 2013 *)
CROSSREFS
Cf. A032611.
Sequence in context: A048059 A106076 A006489 * A289701 A250402 A356383
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
STATUS
approved