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A369957
Primes p such that p - 3 and p + 3 are triprimes.
1
47, 73, 113, 127, 151, 167, 233, 239, 241, 313, 409, 431, 433, 439, 521, 593, 599, 601, 607, 719, 727, 967, 1031, 1087, 1249, 1409, 1439, 1471, 1559, 1601, 1831, 1913, 1993, 2089, 2161, 2273, 2281, 2287, 2311, 2351, 2393, 2633, 2689, 2711, 2729, 2767, 2833, 2879, 3079, 3313, 3319, 3359, 3511
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
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