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 A261821 Minimal nested palindromic primes with seed 4. 2
 4, 11411, 1114111, 18111411181, 741811141118147, 1674181114111814761, 90167418111411181476109, 3901674181114111814761093, 14390167418111411181476109341, 9143901674181114111814761093419, 75914390167418111411181476109341957 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 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 have a(n-1) in the middle.  Then (a(n)) is the sequence of minimal nested palindromic primes with seed s. LINKS Clark Kimberling, Table of n, a(n) for n = 1..200 EXAMPLE As a triangle: .........4 .......11411 ......1114111 ....18111411181 ..741811141118147 1674181114111814761 MATHEMATICA s = {4}; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#]]]] &]; AppendTo[s, tmp], {15}]; s (* Peter J. C. Moses, Sep 01 2015 *) CROSSREFS Cf. A261881 (seed 0, with guide to related sequences). Sequence in context: A058417 A352497 A191592 * A151587 A193137 A280545 Adjacent sequences:  A261818 A261819 A261820 * A261822 A261823 A261824 KEYWORD nonn,easy,base AUTHOR Clark Kimberling, Sep 23 2015 STATUS approved

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Last modified May 29 07:24 EDT 2022. Contains 354122 sequences. (Running on oeis4.)