A262661 Minimal nested palindromic base-8 primes with seed 1; see Comments.

1, 111, 1411141, 12141114121, 10412141114121401, 11610412141114121401611, 171161041214111412140161171, 303171161041214111412140161171303, 3230317116104121411141214016117130323, 71323031711610412141114121401611713032317

Offset

1,2

Comments

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.

Links

Clark Kimberling, Table of n, a(n) for n = 1..300

Example

a(3) = 1411141 is the least base-8 prime having a(2) = 111 in its middle. Triangular format:
           1
          111
        1411141
      12141114121
   10412141114121401
11610412141114121401611

Mathematica

s = {1}; base = 8; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s  (* A262661 *)
Map[FromDigits[ToString[#], base] &, s]  (* A262662 *)
(* Peter J. C. Moses, Sep 01 2015 *)

Crossrefs

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

Sequence in context: A176194 A379243 A261820 * A156407 A292155 A341011

Adjacent sequences: A262658 A262659 A262660 * A262662 A262663 A262664

Keyword

nonn,easy,base

Author

Clark Kimberling, Oct 31 2015

Status

approved