cp's OEIS Frontend

A075807 Numbers n such that n-th prime is palindromic.

%I A075807 #28 Sep 08 2022 08:45:07
%S A075807 1,2,3,4,5,26,32,36,42,43,65,71,74,76,129,134,138,139,157,158,1263,
%T A075807 1285,1293,1367,1377,1483,1519,1528,1583,1635,1647,1682,1726,1805,
%U A075807 1814,1867,1897,1917,1928,2009,2060,2083,2117,2196,2250,2260,3255,3267,3285
%N A075807 Numbers n such that n-th prime is palindromic.
%H A075807 Chai Wah Wu, <a href="/A075807/b075807.txt">Table of n, a(n) for n = 1..10000</a> (n = 1..781 from Vincenzo Librandi, n = 782..5373 from David A. Corneth)
%F A075807 a(n) = A000720(A002385(n)). - _David A. Corneth_, Mar 24 2019
%e A075807 26th prime is 101, which is palindromic.
%p A075807 test := proc(n) local d; d := convert(ithprime(n),base,10); return ListTools[Reverse](d)=d; end; a := []; for n from 1 to 4000 do if test(n) then a := [op(a),n]; end; od; a;
%t A075807 Rest[Flatten[Position[Prime[Range[4000]],_?(IntegerDigits[#] == Reverse[ IntegerDigits[#]]&)]]] (* _Harvey P. Dale_, Jan 26 2014 *)
%o A075807 (Magma) [n: n in [1..3500] | Intseq(NthPrime(n), 10) eq Reverse(Intseq(NthPrime(n), 10))]; // _Vincenzo Librandi_, Mar 24 2019
%o A075807 (PARI) isok(n) = my(d=digits(prime(n))); Vecrev(d) == d; \\ _Michel Marcus_, Mar 24 2019
%Y A075807 Cf. A000720, A002385, A069217.
%K A075807 nonn,base
%O A075807 1,2
%A A075807 _Jani Melik_, Oct 13 2002
%E A075807 Edited by _Dean Hickerson_, Oct 21 2002