A032668 - OEIS

A032668

Digit '5' concatenated with a(n) is a prime.

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

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OFFSET

1,1

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

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

Adjacent sequences: A032665 A032666 A032667 * A032669 A032670 A032671

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1998

STATUS

approved