A167513 - OEIS

%I #13 Jul 22 2025 07:28:46

%S 7,11,17,53,71,101,113,131,137,149,167,173,179,197,311,317,347,353,

%T 383,557,599,701,761,773,1031,1049,1061,1109,1163,1193,1223,1277,1289,

%U 1307,1319,1361,1373,1427,1439,1553,1559,1571,1583,1607,1619,1709,1787,1847

%N Primes p such that (p reversed)-4 is also prime.

%H Vincenzo Librandi, <a href="/A167513/b167513.txt">Table of n, a(n) for n = 1..1000</a>

%e 71->17-4=13; 53->35-4=31; 137->731-4=727.

%t Select[Prime[Range[2, 300]], PrimeQ[FromDigits[Reverse[IntegerDigits[#]]] - 4]&] (* _Vincenzo Librandi_, Apr 15 2013 *)

%o (Magma) [p: p in PrimesInInterval(5,2000) | IsPrime(q-4) where q is Seqint(Reverse(Intseq(p)))]; // _Bruno Berselli_, Apr 15 2013

%K nonn,base,easy

%O 1,1

%A _Vincenzo Librandi_, Nov 05 2009

%E Corrected (379 replaced by 383) and extended by _R. J. Mathar_, Nov 30 2009