cp's OEIS Frontend

A363751 Numbers k such that prime(k) mod k is prime.

%I A363751 #27 Sep 06 2024 11:48:01
%S A363751 3,4,7,8,9,13,15,16,18,20,22,24,26,28,30,31,32,33,34,36,38,39,40,42,
%T A363751 43,44,45,47,48,49,50,51,52,53,55,57,59,60,65,66,69,72,73,74,76,78,82,
%U A363751 84,86,88,90,92,96,98,100,102,106,108,112,116,120,126,128,130
%N A363751 Numbers k such that prime(k) mod k is prime.
%H A363751 Amiram Eldar, <a href="/A363751/b363751.txt">Table of n, a(n) for n = 1..10000</a>
%F A363751 a(n) = A000720(A363752(n)).
%e A363751 9 is a term of this sequence as prime(9) mod 9 = 5, which is prime.
%t A363751 Table[If[PrimeQ[Mod[Prime[k], k]], k, Nothing], {k, 1, 100}]
%o A363751 (Python)
%o A363751 from sympy import prime, isprime
%o A363751 a363751=[]
%o A363751 for k in range(1,101):
%o A363751     if isprime(prime(k)%k):
%o A363751         a363751.append(k)
%o A363751 (PARI) isok(k) = isprime(prime(k) % k); \\ _Michel Marcus_, Jun 19 2023
%Y A363751 Cf. A000720, A004648, A363752.
%K A363751 nonn
%O A363751 1,1
%A A363751 _Nicholas Leonard_, Jun 19 2023