OFFSET
1,1
COMMENTS
The first k where k, k + 1 and k + 2 are all terms is 99. There is no k where k, k + 1, k + 2 and k + 3 are all terms, because 3 * t + 2 is divisible by 4 for t = one of these.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 31 is a term because 2 * 31 + 3 = 65 = 5 * 13 and 3 * 31 + 2 = 95 = 5 * 19 are both semiprimes.
MAPLE
filter:= k -> numtheory:-bigomega(3*k+2) = 2 and numtheory:-bigomega(2*k+3) = 2:
select(filter, [$1..1000]);
MATHEMATICA
s = {}; Do[If[2 == PrimeOmega[2*k + 3] == PrimeOmega[3*k + 2], AppendTo[s, k]], {k, 10^3}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, May 05 2024
STATUS
approved