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A032706
Numbers k such that k prefixed by '6' and followed by '1' is prime.
1
0, 3, 4, 6, 9, 10, 12, 13, 15, 21, 22, 27, 30, 31, 36, 42, 45, 48, 49, 52, 55, 57, 58, 66, 69, 70, 76, 78, 79, 84, 87, 91, 96, 97, 99, 100, 103, 105, 109, 112, 114, 115, 121, 123, 126, 129, 133, 138, 144, 147, 151, 156, 163, 165, 168, 175, 178, 186, 187, 196
OFFSET
1,2
LINKS
MATHEMATICA
Select[Range[0, 200], PrimeQ[FromDigits[Join[{6}, IntegerDigits[#], {1}]]]&] (* Harvey P. Dale, Jun 20 2020 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
EXTENSIONS
Offset changed by Andrew Howroyd, Aug 11 2024
STATUS
approved