login
A364147
Prime numbers that are the exact average of five consecutive odd semiprimes.
6
101, 677, 743, 811, 907, 1039, 1109, 1129, 1301, 1373, 1381, 1567, 1789, 1931, 1949, 1979, 2029, 2447, 2621, 2663, 2731, 2879, 2909, 2971, 3119, 3187, 3221, 3319, 3529, 3631, 3677, 3803, 3823, 3943, 4201, 4253, 4549, 4597, 4637, 4643, 4649, 4801, 4951, 5119, 5189, 5431, 5987, 6053, 6151, 6311
OFFSET
1,1
LINKS
EXAMPLE
101 is a term because (91 + 93 + 95 + 111 + 115)/5 = 101 is prime.
743 is a term because (737 + 737 + 745 + 749 + 753)/5 = 743 is prime.
MAPLE
N:= 10^4: # for terms involving semiprimes up to N
OSP:= select(t -> numtheory:-bigomega(t) = 2, [seq(i, i=1..N, 2)]):
select(t -> t::integer and isprime(t), add(OSP[i..-6+i], i=1..5)/5); # Robert Israel, Aug 11 2023
MATHEMATICA
Select[Mean /@ Partition[Select[Range[1, 6500, 2], PrimeOmega[#] == 2 &], 5, 1], PrimeQ] (* Amiram Eldar, Jul 11 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Elmo R. Oliveira, Jul 10 2023
STATUS
approved