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 A307342 #24 Nov 13 2024 16:30:26 %S A307342 24,36,40,54,56,60,84,88,90,100,104,126,132,135,136,140,150,152,156, %T A307342 184,189,196,198,204,210,220,225,228,232,234,248,250,260,276,294,296, %U A307342 297,306,308,315,328,330,340,342,344,348,350,351,364,372,375,376,380,390 %N A307342 Products of four primes, except fourth powers of primes. %C A307342 Numbers with exactly four prime factors (counted with multiplicity) and more than one distinct prime factor. %C A307342 Numbers n such that bigomega(n) = 4 and omega(n) > 1. %t A307342 Select[Range@ 400, And[! PrimePowerQ@ #, PrimeOmega@ # == 4] &] (* _Michael De Vlieger_, Apr 21 2019 *) %t A307342 Select[Range[400],PrimeOmega[#]==4&&PrimeNu[#]>1&] (* _Harvey P. Dale_, Aug 27 2021 *) %o A307342 (Python) %o A307342 import sympy %o A307342 def bigomega(n): return sympy.primeomega(n) %o A307342 def omega(n): return len(sympy.primefactors(n)) %o A307342 print([n for n in range(1, 1000) if bigomega(n) == 4 and omega(n) > 1]) %o A307342 (PARI) isok(n) = (bigomega(n)==4) && (omega(n) > 1); \\ _Michel Marcus_, Apr 03 2019 %Y A307342 Setwise difference of A014613 and A030514. %Y A307342 Union of A046386, A065036, A085986 and A085987. %Y A307342 Cf. A307682. %K A307342 easy,nonn %O A307342 1,1 %A A307342 _Kalle Siukola_, Apr 02 2019