cp's OEIS Frontend

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.

A339911 Numbers k > 1 for which bigomega(k) <= bigomega(k-1)/2, where bigomega gives the number of prime factors, counted with multiplicity.

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%I A339911 #8 Dec 23 2020 04:11:42
%S A339911 5,7,11,13,17,19,23,25,29,31,33,37,41,43,47,49,53,55,57,59,61,65,67,
%T A339911 71,73,79,82,83,85,89,91,97,101,103,107,109,113,121,127,129,131,133,
%U A339911 137,139,141,145,149,151,157,161,163,167,169,173,177,179,181,185,191,193,197,199,201,205,209,211,217,221,223,226,227
%N A339911 Numbers k > 1 for which bigomega(k) <= bigomega(k-1)/2, where bigomega gives the number of prime factors, counted with multiplicity.
%H A339911 Antti Karttunen, <a href="/A339911/b339911.txt">Table of n, a(n) for n = 1..17515; all terms <= 65537</a>
%t A339911 Select[Range[3, 227, 2], PrimeOmega[#] <= PrimeOmega[# - 1]/2 &] (* _Michael De Vlieger_, Dec 22 2020 *)
%o A339911 (PARI) isA339911(n) = ((n>1)&&((2*bigomega(n))<=bigomega(n-1)));
%Y A339911 Cf. A001222.
%Y A339911 Subsequence of A339910.
%Y A339911 Cf. A339908, A339912 for subsequences.
%K A339911 nonn
%O A339911 1,1
%A A339911 _Antti Karttunen_, Dec 22 2020