A262661 - OEIS

%I #6 Nov 09 2015 16:16:15

%S 1,111,1411141,12141114121,10412141114121401,11610412141114121401611,

%T 171161041214111412140161171,303171161041214111412140161171303,

%U 3230317116104121411141214016117130323,71323031711610412141114121401611713032317

%N Minimal nested palindromic base-8 primes with seed 1; see Comments.

%C Using only base-8 digits 0,1,2,3,4,5,6,7 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-8 primes with seed s.

%H Clark Kimberling, <a href="/A262661/b262661.txt">Table of n, a(n) for n = 1..300</a>

%e a(3) = 1411141 is the least base-8 prime having a(2) = 111 in its middle. Triangular format:

%e            1

%e           111

%e         1411141

%e       12141114121

%e    10412141114121401

%e 11610412141114121401611

%t s = {1}; base = 8; 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  (* A262661 *)

%t Map[FromDigits[ToString[#], base] &, s]  (* A262662 *)

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

%Y Cf. A261881 (base 10), A262662, A262627.

%K nonn,easy,base

%O 1,2

%A _Clark Kimberling_, Oct 31 2015