OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 25 because with a(2) = 10, 25, 25 - 10 = 15 and 25 + 10 = 35 are all semiprimes, and none of the semiprimes between 10 and 25 work.
MAPLE
R:= 4: count:= 0: x:= 4:
for i from 5 while count < 100 do
if andmap(t -> numtheory:-bigomega(t)=2, [i, i+x, i-x]) then
R:= R, i; x:= i; count:= count+1
fi
od:
R;
MATHEMATICA
s = {m=4}; Do[p = m + 4; While[{2, 2, 2} != PrimeOmega[{p, m + p, p -
m}], p++]; AppendTo[s, m = p], {100}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, Mar 17 2023
STATUS
approved