2,1

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 having a(n-1) in the middle. Then (a(n)) is the sequence of minimal nested palindromic primes with seed s. (For A260444, the seed is not an integer, so that the offset is 2.)

Clark Kimberling, Table of n, a(n) for n = 2..200

As a triangle:

0000000

19000000091

1190000000911

36119000000091163

953611900000009116359

9095361190000000911635909

790953611900000009116359097

s0 = "0000000"; s = {ToExpression[s0]}; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s], 10, Max[StringLength[s0], Length[IntegerDigits[Last[s]]]]], Reverse[#]]&[IntegerDigits[#]]]] &]; AppendTo[s, tmp], {10}]; s0 <> ", " <> StringTake[ToString[Rest[s]], {2, -2}]

(* Peter J. C. Moses, Sep 23 2015 *)

Cf. A261881.

Sequence in context: A270895 A273186 A185932 * A317288 A234397 A234194

Adjacent sequences: A262530 A262531 A262532 * A262534 A262535 A262536

nonn,base,easy

Clark Kimberling, Sep 24 2015

approved