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 A339912 #11 Jan 11 2024 16:18:12 %S A339912 13,17,19,29,31,33,37,41,43,49,53,61,65,67,71,73,79,89,97,101,103,109, %T A339912 113,121,127,129,131,137,139,145,149,151,157,161,163,169,173,177,181, %U A339912 191,193,197,199,201,209,211,217,223,229,233,239,241,251,253,257,265,269,271,277,281,283,289,293,301,305,307,311,313 %N A339912 Numbers k > 1 for which bigomega(k) < bigomega(k-1)/2, where bigomega gives the number of prime factors, counted with multiplicity. %H A339912 Antti Karttunen, <a href="/A339912/b339912.txt">Table of n, a(n) for n = 1..12313; all terms <= 65537</a> %t A339912 Select[Range[3, 313, 2], PrimeOmega[#] < PrimeOmega[# - 1]/2 &] (* _Michael De Vlieger_, Dec 22 2020 *) %t A339912 Flatten[Position[Partition[PrimeOmega[Range[400]],2,1],_?(#[[2]]<#[[1]]/2&),1,Heads->False]]+1 (* _Harvey P. Dale_, Jan 11 2024 *) %o A339912 (PARI) isA339912(n) = ((n>1)&&((2*bigomega(n))<bigomega(n-1))); %Y A339912 Cf. A001222. %Y A339912 Subsequence of A339911 and of A339910. %Y A339912 Cf. also A339908. %K A339912 nonn %O A339912 1,1 %A A339912 _Antti Karttunen_, Dec 22 2020