%I #23 Apr 28 2021 04:29:52
%S 1,2,3,5,50,65,75,90,95,156,176,186,191,363,378,393,398,459,464,5150,
%T 5250,5300,5655,5705,6210,6360,6410,6665,6915,6965,7170,7370,7725,
%U 7775,8030,8180,8280,8330,8735,8985,9090,9240,9695,9945,9995,15051,15101,15201,15351,15401,15506,15756
%N Numbers k such that 2k + 1 is a palindromic prime.
%H Daniel Starodubtsev, <a href="/A322947/b322947.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = (A002385(n+1) - 1)/2. - _Rémy Sigrist_, Jan 01 2019
%e 5 is in the sequence, because 2 * 5 + 1 = 11 is a prime palindrome.
%t Select[Range[16000], And[PrimeQ@ #, PalindromeQ@ #] &[2 # + 1] &] (* _Michael De Vlieger_, Jan 01 2019 *)
%o (PARI) isok(n) = my(p=2*n+1, d=digits(p)); isprime(p) && (Vecrev(d) == d); \\ _Michel Marcus_, Jan 01 2019
%Y Cf. A002385 (palindromic primes).
%K nonn,base
%O 1,2
%A _Daniel Starodubtsev_, Dec 31 2018