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A050784 Palindromic primes containing no pair of consecutive equal digits. 3
2, 3, 5, 7, 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, 10301, 10501, 10601, 12421, 12721, 12821, 13831, 13931, 14341, 14741, 15451, 16061, 16361, 16561, 17471, 17971, 18181, 18481, 19391, 19891, 30103, 30203 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

nextL:= proc(L) local V, j, n, k;

  n:= LinearAlgebra:-Dimension(L);

  V:= L;

  for j from n to 1 by -1 do

    V[j]:= V[j]+1;

    if j > 1 then if V[j] = V[j-1] then V[j]:= V[j]+1 fi

    elif member(V[j], [2, 8]) then V[j]:= V[j]+1

    elif member(V[j], [4, 5, 6]) then V[j]:= 7

    fi;

    if V[j] <= 9 then

      for k from j+1 to n do if (k-j)::odd then V[k]:= 0 else V[k]:= 1 fi od;

      return V

    fi;

  od;

  Vector(n+1, i -> i mod 2)

end proc:

Pali:= proc(L)

  local i, n;

  n:= LinearAlgebra:-Dimension(L);

  add(L[i]*10^(2*n-i-1), i=1..n)+add(L[i]*10^(i-1), i=1..n-1)

end proc:

V:= <5>: Res:= 2, 3, 5: count:= 3:

while count < 100 do

  V:= nextL(V);

  x:= Pali(V);

  if isprime(x) then count:= count+1; Res:= Res, x fi;

od:

Res; # Robert Israel, Feb 07 2019

MATHEMATICA

Select[Prime[Range[3280]], Reverse[x=IntegerDigits[#]]==x&&FreeQ[Differences[x], 0]&] (* Jayanta Basu, Jun 01 2013 *)

CROSSREFS

Cf. A050783, A030147, A050757, A046075.

Sequence in context: A092909 A080437 A092908 * A030150 A029977 A052019

Adjacent sequences:  A050781 A050782 A050783 * A050785 A050786 A050787

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Sep 15 1999

STATUS

approved

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Last modified November 14 02:19 EST 2019. Contains 329108 sequences. (Running on oeis4.)