A309381 - OEIS

%I #12 Mar 03 2022 10:54:29

%S 7,31,37,67,73,613,991,1087,1117,2467,3301,3307,3607,4561,4987,4993,

%T 6367,6373,8263,8641,9643,10903,11827,11953,12373,12547,15187,15901,

%U 17047,18043,19603,20353,21751,23671,25147,28837,31033,31231,37957,38707,38917,43201,44383,46021,49627

%N Lucky primes k such that k+6 is also a lucky prime.

%C A031157(k) for k such that A309334(k)=6.

%C The minimum gap between lucky primes (after the first) is 6.

%H Robert Israel, <a href="/A309381/b309381.txt">Table of n, a(n) for n = 1..1615</a>

%e 37 and 37+6=43 are both lucky primes, so 37 is in the sequence.

%p N:= 10^5: # for terms <= N

%p L:= [seq(i,i=1..N+6,2)]:

%p for n from 2 while n < nops(L) do

%p   r:= L[n];

%p   L:= subsop(seq(r*i=NULL, i=1..nops(L)/r), L);

%p od:

%p L:= convert(select(isprime,L),set):

%p A:= L intersect map(`-`,L,6):

%p sort(convert(A,list));

%Y Cf. A031157, A309334.

%K nonn

%O 1,1

%A _Robert Israel_, Jul 26 2019