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

Author

Carlos Rivera, Dec 19 2013

Keywords

• nonn
• base
• hard

Comments

Results of my search up to 2^32.

Examples

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

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

Crossrefs

Cf. A039993, A039997.

Extensions

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