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A032732
Numbers k such that k prefixed by '7' and followed by '9' is prime.
2
0, 1, 3, 6, 10, 12, 15, 21, 22, 30, 34, 36, 45, 48, 49, 52, 54, 55, 58, 63, 64, 66, 69, 75, 78, 82, 87, 91, 94, 103, 105, 106, 108, 111, 112, 120, 124, 132, 133, 135, 138, 139, 141, 142, 147, 154, 156, 169, 171, 178, 180, 184, 187, 189, 190, 199, 201, 208, 210
OFFSET
1,3
LINKS
MATHEMATICA
Select[Range[0, 300], PrimeQ[FromDigits[Join[{7}, IntegerDigits[#], {9}]]]&] (* Harvey P. Dale, Dec 03 2021 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
EXTENSIONS
Offset changed by Andrew Howroyd, Aug 13 2024
STATUS
approved