A262498 Minimal nested palindromic primes with seed 1111111.

1111111, 14111111141, 131411111114131, 91314111111141319, 389131411111114131983, 7238913141111111413198327, 16723891314111111141319832761, 381672389131411111114131983276183, 1638167238913141111111413198327618361, 1191638167238913141111111413198327618361911

Offset: 1

Author

Clark Kimberling, Sep 24 2015

Keywords

• nonn
• base
• easy

Comments

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.

Examples

			As a triangle:
             1111111
           14111111141
         131411111114131
        91314111111141319
      389131411111114131983
    7238913141111111413198327
  16723891314111111141319832761
381672389131411111114131983276183
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A261881.

Programs

Mathematica

s0 = "1111111"; 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 *)