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A050718
Inserting a digit '8' between adjacent decimal digits of n makes a prime.
10
11, 21, 23, 33, 39, 47, 57, 63, 77, 81, 83, 87, 93, 109, 111, 127, 129, 141, 153, 157, 177, 201, 207, 211, 213, 223, 229, 237, 267, 279, 303, 313, 319, 321, 327, 373, 417, 421, 433, 441, 447, 459, 471, 477, 483, 489, 499, 519, 541, 567, 577, 579, 589, 607
OFFSET
1,1
COMMENTS
Arguably 2, 3, 5, and 7 should be in this sequence. - Charles R Greathouse IV, Sep 25 2012
LINKS
EXAMPLE
177 becomes 1(8)7(8)7 which is the prime 18787.
MATHEMATICA
Select[Range[10, 700], PrimeQ[FromDigits[Riffle[IntegerDigits[#], 8]]]&] (* Harvey P. Dale, Sep 18 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Aug 15 1999
STATUS
approved