cp's OEIS Frontend

A248372 Numbers m such that both p = 52*m + 1 and q = 52*p + 1 are prime.

%I A248372 #23 Jun 14 2025 23:49:07
%S A248372 36,39,60,126,171,189,195,300,315,405,420,435,504,540,570,606,720,756,
%T A248372 816,876,960,1089,1221,1224,1260,1329,1365,1371,1389,1404,1530,1554,
%U A248372 1674,1740,1785,1791,1914,1959,2085,2244,2304,2334,2376,2451,2454,2520,2631,2646,2715,2799,2976
%N A248372 Numbers m such that both p = 52*m + 1 and q = 52*p + 1 are prime.
%C A248372 All terms are divisible by 3, because if m == 1 or 2 (mod 3), either q or p is divisible by 3.
%H A248372 Jens Kruse Andersen, <a href="/A248372/b248372.txt">Table of n, a(n) for n = 1..10000</a>
%t A248372 s={};Do[If[PrimeQ[p=52*n+1]&&PrimeQ[52*p+1],AppendTo[s,n]],{n,3000}];s
%t A248372 Select[Range[3000],AllTrue[{52#+1,53+2704#},PrimeQ]&] (* _Harvey P. Dale_, Mar 21 2025 *)
%o A248372 (PARI)
%o A248372 for(n=1,10^4,p=52*n+1;if(isprime(p)&&isprime(52*p+1),print1(n,", "))) \\ _Derek Orr_, Oct 06 2014
%Y A248372 Subsequence of A248221.
%Y A248372 Cf. A033210, A142508, A171517, A248221, A248368.
%K A248372 nonn
%O A248372 1,1
%A A248372 _Zak Seidov_, Oct 05 2014