A261825 - OEIS

%I #8 Sep 29 2015 12:50:07

%S 8,181,1218121,15121812151,111512181215111,3311151218121511133,

%T 133111512181215111331,1113311151218121511133111,

%U 1141113311151218121511133111411,73114111331115121812151113311141137,30273114111331115121812151113311141137203

%N Minimal nested palindromic primes with seed 8.

%C Let s be a palindrome and put a(1) = s.  Let a(2) be the least palindromic prime having s in the middle; for n > 2, let a(n) be the least palindromic prime have a(n-1) in the middle.  Then (a(n)) is the sequence of minimal nested palindromic primes with seed s.

%H Clark Kimberling, <a href="/A261825/b261825.txt">Table of n, a(n) for n = 1..200</a>

%e As a triangle:

%e .........8

%e ........181

%e ......1218121

%e ....15121812151

%e ..111512181215111

%e 3311151218121511133

%t s = {8}; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#]]]] &]; AppendTo[s, tmp], {15}]; s

%t (* _Peter J. C. Moses_, Sep 01 2015 *)

%Y Cf. A261881 (seed 0, with guide to related sequences).

%K nonn,easy,base

%O 1,1

%A _Clark Kimberling_, Sep 23 2015