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 A029971 Palindromic primes in base 3. 9
 2, 13, 23, 151, 173, 233, 757, 937, 1093, 1249, 1429, 1487, 1667, 1733, 1823, 1913, 1979, 2069, 8389, 9103, 10111, 12301, 14951, 16673, 16871, 18593, 60103, 60913, 61507, 63127, 69697, 73243, 78979, 80599, 82003, 82813, 83407, 85027 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Intersection of A000040 and A014190. - Michel Marcus, Aug 19 2015 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..3004 P. De Geest, World!Of Palindromic Primes MAPLE N:= 14: # to get all terms < 3^N Res:= 2: digrev:=proc(n) local L;   L:= convert(n, base, 3);   add(L[-i]*3^(i-1), i=1..nops(L)) end proc; for d from 2 to N do   if d::even then     m:= d/2;     Res:= Res, op(select(isprime, [seq](n*3^m + digrev(n), n=3^(m-1)..3^m-1)));   else     m:= (d-1)/2;     Res:= Res, op(select(isprime, [seq](seq(n*3^(m+1)+y*3^m+digrev(n),       y=0..2), n=3^(m-1)..3^m-1)));   fi od: Res; # Robert Israel, Aug 19 2015 MATHEMATICA Do[s = RealDigits[n, 3][[1]]; If[PrimeQ[n], If[FromDigits[s] == FromDigits[Reverse[s]], Print[n]]], {n, 1, 8500}] Select[Prime[Range[8300]], Reverse[x = IntegerDigits[#, 3]] == x &] (* Jayanta Basu, Jun 23 2013 *) PROG (PARI) lista(nn) = forprime(p=2, nn, if ((d=digits(p, 3)) && (Vecrev(d)==d), print1(p, ", "))); \\ Michel Marcus, Aug 19 2015 CROSSREFS Cf. A117698 (in base 3), A014190. Sequence in context: A093301 A079397 A118524 * A243619 A243620 A090526 Adjacent sequences:  A029968 A029969 A029970 * A029972 A029973 A029974 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified December 16 00:55 EST 2018. Contains 318157 sequences. (Running on oeis4.)