A029975 Primes that are palindromic in base 7.

2, 3, 5, 71, 107, 157, 257, 271, 307, 2549, 2647, 2801, 3347, 3697, 3851, 4201, 4397, 4649, 4951, 5399, 5651, 5749, 5903, 6449, 6701, 7451, 7703, 8053, 8501, 8753, 9103, 9551, 10007, 10357, 10903, 11057, 11953, 12157, 12409, 13109

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• P. De Geest, World!Of Palindromic Primes

Programs

Mathematica

f[n_]:=FromDigits[RealDigits[n,7][[1]]]==FromDigits[Reverse[RealDigits[n,7][[1]]]]; lst={}; Do[p=Prime[n]; If[f[p],AppendTo[lst,p]],{n,8!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 10 2009 *)
pb7Q[n_]:=Module[{idn7=IntegerDigits[n,7]},idn7==Reverse[idn7]]; Select[ Prime[ Range[1600]],pb7Q] (* Harvey P. Dale, Nov 21 2015 *)