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%I A321504 #12 Jul 17 2021 07:01:02
%S A321504 7314,8294,8645,9009,10659,11570,11780,11934,13299,13629,13845,14420,
%T A321504 15105,15554,16554,16835,17204,17390,17654,17765,18095,18290,18444,
%U A321504 18920,19005,19019,19095,19227,20349,20405,20769,21164,21489,21735,22010,22154,22659,23001,23114,23484,23529,23540,23919,24395
%N A321504 Numbers k such that k and k+1 each have at least 4 distinct prime factors.
%C A321504 Equals A140078 up to a(123) but a({124, 214, 219, 276, 321, 415, ...}) = { 38570, 51414, 51765, 58695, 62985, 71070, ...} are not in A140078, see A321494.
%H A321504 M. F. Hasler, <a href="/A321504/b321504.txt">Table of n, a(n) for n = 1..10000</a>
%t A321504 SequencePosition[Table[If[PrimeNu[n]>3,1,0],{n,25000}],{1,1}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 29 2019 *)
%o A321504 (PARI) is(n)=omega(n)>=4&&omega(n+1)>=4
%Y A321504 Cf. A140078, A321494.
%Y A321504 Cf. A321505, A321506 (variant for k=5 & k=6 prime factors).
%K A321504 nonn
%O A321504 1,1
%A A321504 _M. F. Hasler_, Nov 12 2018

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