login
A032668
Digit '5' concatenated with a(n) is a prime.
3
3, 9, 21, 23, 41, 47, 57, 63, 69, 71, 77, 87, 93, 99, 101, 107, 113, 119, 147, 153, 167, 171, 179, 189, 197, 209, 227, 231, 233, 237, 261, 273, 279, 281, 297, 303, 309, 323, 333, 347, 351, 381, 387, 393, 399, 407, 413, 417, 419, 431, 437, 441
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[500], PrimeQ[FromDigits[Join[{5}, IntegerDigits[#]]]]&] (* Harvey P. Dale, Mar 23 2012 *)
CROSSREFS
Sequence in context: A330987 A365919 A109612 * A050839 A032640 A245202
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1998
STATUS
approved