A174229 Natural numbers n such that the concatenation n^3//1331, i.e., a cube and 11^3, is a prime number.

2, 6, 8, 14, 21, 38, 39, 51, 54, 65, 68, 78, 80, 93, 104, 107, 114, 117, 119, 125, 135, 137, 146, 147, 152, 153, 158, 159, 167, 186, 206, 225, 243, 246, 248, 257, 258, 269, 270, 272, 278, 284, 290, 291, 306, 311, 317, 321, 323, 324, 369, 372, 387, 390, 399, 404, 410, 414, 425

Offset: 1

Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 13 2010

Keywords

• base
• nonn

Comments

See comments and references for A174213.

Examples

			2^3 = 8, 81331 = prime(7958) => a(1) = 2;
6^3 = 216, 2161331 = prime(160048) => a(2) = 6.
		

Crossrefs

Cf. A168327, A168417, A173836, A174213.

Programs

PARI

isok(n) = isprime(eval(concat(Str(n^3), Str(1331)))); \\ Michel Marcus, Jul 20 2017

Extensions

More terms from Michel Marcus, Jul 20 2017