A341599 - OEIS

%I #9 Feb 17 2021 15:06:09

%S 2,3,19,29,47,59,61,73,103,109,149,173,179,199,227,271,379,383,463,

%T 467,479,499,509,541,557,593,607,673,733,761,829,947,953,1019,1049,

%U 1061,1063,1109,1259,1307,1319,1373,1399,1489,1607,1699,1709,1721,1723,1741,1801,1889,1931,1979,1987,2029,2039

%N Primes p such that p + 2*Sum({k > 0 : p+k and p-k are both prime}) is prime.

%H Robert Israel, <a href="/A341599/b341599.txt">Table of n, a(n) for n = 1..10000</a>

%e a(4) = 29 is a term because the values of k for which 29+k and 29-k are prime are 12, 18 and 24, and 19+2*(12+18+24) = 127 which is prime.

%p filter:= proc(n) local i;

%p   isprime(n + 2*add(`if`(isprime(n+i) and isprime(n-i),i,0), i=6..n-5,6) + `if`(isprime(2*n - 3),2*n-6,0))

%p end proc:

%p select(filter, [seq(ithprime(i),i=1..1000)]);

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Feb 15 2021