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 A261826 Minimal nested palindromic primes with seed 9. 2

%I

%S 9,191,71917,147191741,3914719174193,139147191741931,

%T 7213914719174193127,33721391471917419312733,

%U 9337213914719174193127339,1719337213914719174193127339171,11171933721391471917419312733917111,1111719337213914719174193127339171111

%N Minimal nested palindromic primes with seed 9.

%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="/A261826/b261826.txt">Table of n, a(n) for n = 1..200</a>

%e As a triangle:

%e .......9

%e ......191

%e .....71917

%e ...147191741

%e .3914719174193

%e 139147191741931

%t s = {9}; 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

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Last modified August 8 21:55 EDT 2022. Contains 356016 sequences. (Running on oeis4.)