A229908 - OEIS

%I #24 Oct 19 2014 15:57:16

%S 2,13,13,37,113,113,137,1237,1373,1733,1733,11317,11731,12713,19973,

%T 91733,113173,113371,113371,173347,991733,1123379,1134673,1137991,

%U 1237199,2333719,7433719,11133719,11399173,11399173,11791733,37914713,97433719,113217397,113217397,113337199,113337199,113337199,1113371999,1113371999,1113991733,1139917321,1139917321,1139917333

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

%C Results of my search up to 2^32.

%H Giovanni Resta, <a href="/A229908/b229908.txt">Table of n, a(n) for n = 1..65</a> (terms < 3.5*10^12)

%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_724.htm">Puzzle 724. Extending the OEIS sequence A229908</a>

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

%Y Cf. A039993, A039997.

%K nonn,base,hard

%O 1,1

%A _Carlos Rivera_, Dec 19 2013

%E Missing a(19) from _Giovanni Resta_, Jan 25 2014