A262498 - OEIS

%I #10 Oct 02 2015 13:07:05

%S 1111111,14111111141,131411111114131,91314111111141319,

%T 389131411111114131983,7238913141111111413198327,

%U 16723891314111111141319832761,381672389131411111114131983276183,1638167238913141111111413198327618361,1191638167238913141111111413198327618361911

%N Minimal nested palindromic primes with seed 1111111.

%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 having 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="/A262498/b262498.txt">Table of n, a(n) for n = 1..200</a>

%e As a triangle:

%e              1111111

%e            14111111141

%e          131411111114131

%e         91314111111141319

%e       389131411111114131983

%e     7238913141111111413198327

%e   16723891314111111141319832761

%e 381672389131411111114131983276183

%t 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}]

%t (* _Peter J. C. Moses_, Sep 23 2015 *)

%Y Cf. A261881.

%K nonn,base,easy

%O 1,1

%A _Clark Kimberling_, Sep 24 2015