A050784 Palindromic primes containing no pair of consecutive equal digits.

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

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. A002385, A050783, A030147, A050757, A046075.

Sequence in context: A092909 A080437 A092908 * A030150 A343675 A029977

Adjacent sequences: A050781 A050782 A050783 * A050785 A050786 A050787

Keyword

nonn,base

Author

Patrick De Geest, Sep 15 1999

Status

approved