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

Author

Patrick De Geest, Sep 15 1999

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A002385, A050783, A030147, A050757, A046075.

Programs

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 *)