A262659 - OEIS

%I #6 Oct 31 2015 15:11:32

%S 0,13031,511303115,3351130311533,333511303115333,1033351130311533301,

%T 1051033351130311533301501,35105103335113031153330150153,

%U 12135105103335113031153330150153121,12012135105103335113031153330150153121021,331201213510510333511303115333015015312102133

%N Minimal nested palindromic base-8 primes with seed 0; 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="/A262659/b262659.txt">Table of n, a(n) for n = 1..300</a>

%e a(3) = 511303115 is the least base-8 prime having a(2) = 13031 in its middle. Triangular format:

%e          0

%e        13031

%e      511303115

%e    3351130311533

%e   333511303115333

%e 1033351130311533301

%t s = {0}; 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  (* A262659 *)

%t Map[FromDigits[ToString[#], base] &, s]  (* A262660 *)

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

%Y Cf. A261881 (base 10), A262660, A262627.

%K nonn,easy,base

%O 1,2

%A _Clark Kimberling_, Oct 27 2015