cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A262497 Minimal nested palindromic primes with seed 11111.

Original entry on oeis.org

11111, 121111121, 71211111217, 3712111112173, 98371211111217389, 129837121111121738921, 3312983712111112173892133, 1063312983712111112173892133601, 12106331298371211111217389213360121, 781210633129837121111121738921336012187
Offset: 1

Views

Author

Clark Kimberling, Sep 24 2015

Keywords

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:
             11111
           121111121
          71211111217
         3712111112173
       98371211111217389
     129837121111121738921
   3312983712111112173892133
1063312983712111112173892133601
		

Crossrefs

Cf. A261881.

Programs

  • Mathematica
    s0 = "11111"; 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 *)