A032722 Numbers k such that k prefixed by '5' and followed by '7' is prime.

4, 5, 7, 8, 10, 14, 16, 19, 22, 23, 29, 34, 38, 40, 41, 43, 47, 50, 52, 55, 64, 65, 71, 73, 80, 82, 85, 86, 89, 92, 98, 104, 113, 115, 119, 121, 125, 128, 130, 134, 140, 142, 143, 148, 151, 157, 160, 163, 164, 176, 178, 179, 181, 182, 190, 197, 202, 205, 206, 212

Offset

1,1

Links

Table of n, a(n) for n=1..60.

Mathematica

Select[Range[250], PrimeQ[FromDigits[Join[{5}, IntegerDigits[#], {7}]]]&] (* Harvey P. Dale, Jul 24 2011 *)

Crossrefs

Cf. A032702-A032733.

Sequence in context: A189707 A120163 A088763 * A293856 A098416 A005556

Adjacent sequences: A032719 A032720 A032721 * A032723 A032724 A032725

Keyword

nonn,base

Author

Patrick De Geest, May 15 1998

Extensions

Offset changed by Andrew Howroyd, Aug 13 2024

Status

approved