OFFSET
1,1
COMMENTS
Primes p such that at least one of 2*p-1 and 2*p+1 is prime, and at least one of 4*p-1 and 4*p+1 is prime.
Primes p such that either 2*p-1 and 4*p+1 are prime, or 2*p+1 and 4*p-1 are prime.
Primes p such that 4*p is in A333197.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 5 is a member because 5, 2*5+1=11 and 4*5-1=19 are primes.
MAPLE
filter:= proc(t) isprime(t) and (isprime(2*t+1) or isprime(2*t-1)) and (isprime(4*t+1) or isprime(4*t-1)) end proc:
select(filter, [2, seq(i, i=3..10000, 2)]);
MATHEMATICA
Select[Prime[Range[700]], AnyTrue[2#+{1, -1}, PrimeQ]&&AnyTrue[4#+{1, -1}, PrimeQ] &] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 17 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Apr 12 2020
STATUS
approved