A062231 Numbers k such that the smoothly undulating palindromic number (97*10^k - 79)/99 is a prime.

9, 27, 45, 237

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=27 -> (97*10^27 - 79)/99 = 979797979797979797979797979.
		

Links

• Patrick De Geest, SUPP Reference Table - 979
• Index entries for sequences related to smoothly undulating palindromic primes

Crossrefs

Cf. A062209-A062232, A059758, A032758.

Programs

Mathematica

Select[Range[1,239,2],PrimeQ[FromDigits[PadRight[{},#,{9,7}]]]&] (* Harvey P. Dale, Mar 24 2021 *)

Extensions

Edited by Ray Chandler, Aug 17 2011