OFFSET
1,1
COMMENTS
Primes p such that p - 3 and p + 3 each have 3 prime factors, counted with multiplicity.
Primes p such that one of p - 3 and p + 3 is 4 times a prime and the other is 2 times a semiprime.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 113 is a term because 113 is prime, and 110 = 2 * 5 * 11 and 116 = 2^2 * 29 are triprimes.
MAPLE
filter:= proc(n)
isprime(n) and numtheory:-bigomega(n-3) = 3 and numtheory:-bigomega(n+3) = 3
end proc:
select(filter, [seq(i, i=3..20000, 2)]);
MATHEMATICA
s = {}; p = 5; Do[If[{3, 3} == PrimeOmega[{p - 3, p + 3}],
AppendTo[s, p]]; p = NextPrime[p], {500}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, Feb 07 2024
STATUS
approved