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A186698 Next prime after n-th palindrome. 2
2, 3, 5, 5, 7, 7, 11, 11, 11, 13, 23, 37, 47, 59, 67, 79, 89, 101, 103, 113, 127, 137, 149, 157, 163, 173, 191, 193, 211, 223, 223, 233, 251, 257, 263, 277, 283, 293, 307, 317, 331, 337, 347, 359, 367, 379, 389, 397, 409, 419, 431, 439, 449, 457, 467, 479, 487, 499, 509, 521, 541, 541, 547, 557, 569, 577, 587, 599, 607, 617, 631, 641, 647 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are infinitely many n for which a(n+1) = a(n).  For example, when 10^k + 1 is composite, 10^k - 1 and 10^k + 1 are successive palindromes which have the same next prime. - Robert Israel, Nov 04 2015

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

MAPLE

digrev:= proc(x) option remember; local t;

   t:= x mod 10;

   t*10^ilog10(x)+procname((x-t)/10)

end proc:

for x from 0 to 9 do digrev(x):= x od:

N:=6;

Pals:= $1..9:

for d from 2 to N do

  if d::even then

    m:= d/2;

    Pals:= Pals, seq(n*10^m + digrev(n), n=10^(m-1)..10^m-1);

  else

    m:= (d-1)/2;

    Pals:= Pals, seq(seq(n*10^(m+1)+y*10^m+digrev(n), y=0..9), n=10^(m-1)..10^m-1);

  fi

od:

Pals:=[Pals]:

map(nextprime, Pals); # Robert Israel, Nov 04 2015

CROSSREFS

Cf. A014208, A186697.

Sequence in context: A159477 A268101 A123318 * A234345 A111060 A082432

Adjacent sequences:  A186695 A186696 A186697 * A186699 A186700 A186701

KEYWORD

nonn,base

AUTHOR

Harvey P. Dale, Feb 25 2011

STATUS

approved

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Last modified April 22 16:32 EDT 2021. Contains 343177 sequences. (Running on oeis4.)