This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A345381 #11 Dec 18 2021 08:07:20 %S A345381 12,18,20,24,28,40,44,45,48,50,52,54,56,63,68,75,76,80,88,92,96,98,99, %T A345381 104,112,116,117,124,135,136,147,148,152,153,160,162,164,171,172,175, %U A345381 176,184,188,189,192,207,208,212,224,232,236,242,244,245,248,250,261,268,272,275 %N A345381 Numbers with exactly 2 semiprime divisors. %C A345381 Numbers of the form p*q^k, where p and q are distinct primes and k>1. %H A345381 Amiram Eldar, <a href="/A345381/b345381.txt">Table of n, a(n) for n = 1..10000</a> %e A345381 50 is in the sequence since it has exactly 2 semiprime divisors, 10 and 25. %t A345381 Select[Range[300], Length[(e = Sort[FactorInteger[#][[;; , 2]]])] == 2 && Min[e] == 1 && Max[e] > 1 &] (* _Amiram Eldar_, Sep 30 2021 *) %o A345381 (Python) %o A345381 from sympy import factorint %o A345381 def ok(n): %o A345381 e = sorted(factorint(n).values()) %o A345381 return len(e) == 2 and e[0] == 1 and e[1] > 1 %o A345381 print([k for k in range(276) if ok(k)]) # _Michael S. Branicky_, Dec 18 2021 %Y A345381 Cf. A001358 (semiprimes). %Y A345381 Supersequence of A054753, A096156. %K A345381 nonn %O A345381 1,1 %A A345381 _Wesley Ivan Hurt_, Jun 16 2021