A102727 - OEIS

A102727

Numbers k such that k1111111 is prime.

6, 7, 10, 13, 25, 36, 43, 54, 73, 75, 96, 99, 103, 105, 108, 112, 115, 150, 157, 171, 189, 208, 223, 228, 237, 262, 264, 292, 300, 312, 328, 340, 349, 351, 361, 372, 379, 388, 391, 409, 421, 424, 435, 444, 459, 465, 466, 481, 484, 501, 504, 508, 510, 535, 552, 565, 579, 580, 586, 610, 612, 619

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

If k=6, then k1111111 = 61111111 (prime).

If k=54, then k1111111 = 541111111 (prime).

If k=108, then k1111111 = 1081111111 (prime).

PROG

(Magma) [ n: n in [1..700] | IsPrime(Seqint([1, 1, 1, 1, 1, 1, 1] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011

CROSSREFS