A032706 Numbers k such that k prefixed by '6' and followed by '1' is prime.

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

Author

Patrick De Geest, May 15 1998

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A032702-A032733.

Programs

Mathematica

Select[Range[0,200],PrimeQ[FromDigits[Join[{6},IntegerDigits[#],{1}]]]&] (* Harvey P. Dale, Jun 20 2020 *)

Extensions

Offset changed by Andrew Howroyd, Aug 11 2024