A062223 Numbers k such that the smoothly undulating palindromic number (74*10^k - 47)/99 is a prime.

5, 17, 2069, 6815, 20417, 25745

Offset: 1

Author

Patrick De Geest and Hans Rosenthal (Hans.Rosenthal(AT)t-online.de), Jun 15 2001

Keywords

• nonn
• base
• more

Comments

Prime versus probable prime status and proofs are given in the author's table.

No further terms < 100000. - Ray Chandler, Aug 17 2011

Examples

			k=17 -> (74*10^17 - 47)/99 = 74747474747474747.
		

Links

• Patrick De Geest, SUPP Reference Table - 747
• Index entries for sequences related to smoothly undulating palindromic primes

Crossrefs

Cf. A062209-A062232, A059758, A032758.

Extensions

Edited by Ray Chandler, Aug 17 2011