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 A367006 #11 Dec 11 2023 08:37:15
%S A367006 0,1,1,2,2,1,2,2,2,2,2,2,3,2,2,5,3,2,3,2,4,3,3,3,2,3,3,4,4,1,3,2,3,5,
%T A367006 3,5,2,3,2,4,4,3,5,3,4,4,4,4,4,3,3,4,4,3,4,3,4,2,5,3,3,4,3,9,5,4,3,5,
%U A367006 4,3,3,2,4,4,1,7,3,4,5,2,1,4,4,6,2,2,4
%N A367006 Number of distinct prime factors of n*2^n - 1.
%C A367006 The numbers n*2^n-1 are called Woodall (or Riesel) numbers.
%H A367006 Amiram Eldar, <a href="/A367006/b367006.txt">Table of n, a(n) for n = 1..865</a>
%F A367006 a(n) = omega(n*2^n - 1) = A001221(A003261(n)).
%t A367006 Table[PrimeNu[n*2^n - 1], {n, 1, 100}] (* _Amiram Eldar_, Dec 11 2023 *)
%o A367006 (PARI) a(n) = omega(n*2^n - 1); \\ _Amiram Eldar_, Dec 11 2023
%Y A367006 Cf. A003261, A001221, A366898, A366899.
%K A367006 nonn
%O A367006 1,4
%A A367006 _Sean A. Irvine_, Oct 31 2023