A192261 Numbers n such that 4n+1 is a palindromic prime.

1, 25, 45, 78, 88, 93, 189, 199, 232, 2575, 2625, 2650, 3105, 3180, 3205, 3585, 3685, 4015, 4090, 4140, 4165, 4545, 4620, 7753, 7878, 8383, 8763, 8788, 8838, 8938, 9318, 9393, 9823, 17829, 17979, 18259, 18309, 18409, 18889, 19344, 19369, 19494, 19849, 19924

Offset: 1

Author

Matevz Markovic, Jul 02 2011

Keywords

• nonn
• base

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..10000
• Wikipedia, Pythagorean primes

Crossrefs

Cf. A002385, A002144, A081220.

Programs

Mathematica

Select[Range[10000],PrimeQ[4#+1]&&PalindromeQ[4#+1]&] (* Harvey P. Dale, Jun 24 2023 *)

PARI

is(n)=n==eval(concat(Vecrev(Str(n))))&&isprime(n);
for(n=1, 1e4, if(is(4*n+1), print1(n, ", "))) \\ Altug Alkan, Nov 04 2015

Formula

{n such that A016813(n) is in A002385}. [Jonathan Vos Post, Jul 17 2011]

Extensions

Prior Mathematica program removed and more terms from Harvey P. Dale, Jun 24 2023