A032730 Numbers k such that k prefixed by '5' and followed by '9' is prime.
0, 6, 9, 11, 17, 18, 20, 27, 30, 39, 41, 44, 47, 51, 56, 63, 65, 66, 68, 74, 77, 83, 84, 86, 87, 93, 105, 110, 116, 119, 122, 123, 132, 134, 141, 143, 144, 147, 153, 159, 165, 167, 171, 174, 176, 182, 183, 185, 186, 189, 192, 194, 200, 206, 218, 224, 225
Offset: 1
Programs
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Mathematica
Select[Range[0,250],PrimeQ[FromDigits[Join[{5},IntegerDigits[#], {9}]]]&] (* Harvey P. Dale, May 09 2011 *)
Extensions
Offset changed by Andrew Howroyd, Aug 13 2024