A262655 - OEIS

%I #8 Oct 31 2015 15:11:06

%S 5,151,11511,5115115,13511511531,5135115115315,15513511511531551,

%T 1155135115115315511,14115513511511531551141,

%U 131411551351151153155114131,51314115513511511531551141315,11551314115513511511531551141315511,11511551314115513511511531551141315511511

%N Minimal nested palindromic base-6 primes with seed 5; see Comments.

%C Using only base-6 digits 0,1,2,3,4,5, 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 base-6 primes with seed s.

%H Clark Kimberling, <a href="/A262655/b262655.txt">Table of n, a(n) for n = 1..300</a>

%e a(3) = 11511 is the least base-6 prime having a(2) = 151 in its middle.

%e Triangular format:

%e         5

%e        151

%e       11511

%e      5115115

%e    13511511531

%e   5135115115315

%t s = {5}; base = 6; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];

%t AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s  (* A262655 *)

%t Map[FromDigits[ToString[#], base] &, s]  (* A262656 *)

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

%Y Cf. A261881 (base 10), A262656, A262627.

%K nonn,easy,base

%O 1,1

%A _Clark Kimberling_, Oct 27 2015