A229908 The least prime that has at least n embedded primes, reading forward and backward.

2, 13, 13, 37, 113, 113, 137, 1237, 1373, 1733, 1733, 11317, 11731, 12713, 19973, 91733, 113173, 113371, 113371, 173347, 991733, 1123379, 1134673, 1137991, 1237199, 2333719, 7433719, 11133719, 11399173, 11399173, 11791733, 37914713, 97433719, 113217397, 113217397, 113337199, 113337199, 113337199, 1113371999, 1113371999, 1113991733, 1139917321, 1139917321, 1139917333

Offset

1,1

Comments

Results of my search up to 2^32.

Links

Giovanni Resta, Table of n, a(n) for n = 1..65 (terms < 3.5*10^12)

C. Rivera, Puzzle 724. Extending the OEIS sequence A229908

Example

Example: a(8) = 1237 because there are the following eight embedded primes: 1237, 2, 23, 3, 37, 7 and 73, 7321.

Crossrefs

Cf. A039993, A039997.

Sequence in context: A065584 A153651 A369411 * A335972 A175270 A320339

Adjacent sequences: A229905 A229906 A229907 * A229909 A229910 A229911

Keyword

nonn,base,hard

Author

Carlos Rivera, Dec 19 2013

Extensions

Missing a(19) from Giovanni Resta, Jan 25 2014

Status

approved