A350375 - OEIS

%I #11 Dec 28 2021 14:51:07

%S 1260,1980,2100,2340,2520,2772,2940,3060,3150,3276,3300,3420,3780,

%T 3900,3960,4140,4200,4284,4410,4680,4788,4950,5040,5100,5148,5220,

%U 5544,5580,5700,5796,5850,5880,5940,6120,6468,6552,6600,6660,6732,6840,6900,7020,7260,7308

%N Numbers with exactly 8 semiprime divisors.

%t q[n_] := DivisorSum[n, 1 &, PrimeOmega[#] == 2 &] == 8; Select[Range[7500], q] (* _Amiram Eldar_, Dec 28 2021 *)

%o (PARI) isok(k) = sumdiv(k, d, bigomega(d)==2) == 8; \\ _Michel Marcus_, Dec 28 2021

%Y Numbers with exactly k semiprime divisors: A346041 (k=1), A345381 (k=2), A345382 (k=3), A350371 (k=4), A350372 (k=5), A350373 (k=6), A350374 (k=7), this sequence (k=8).

%K nonn

%O 1,1

%A _Wesley Ivan Hurt_, Dec 27 2021