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 A066102 #16 Dec 14 2024 20:30:32
%S A066102 0,1,2,3,2,3,2,2,3,3,2,5,2,3,3,4,2,4,3,5,3,3,2,4,4,3,4,5,2,4,3,5,3,3,
%T A066102 3,4,3,3,3,4,3,4,4,5,5,3,3,5,5,5,3,5,3,4,3,4,4,3,4,6,2,4,5,4,3,4,3,5,
%U A066102 3,4,2,5,2,4,6,6,3,4,4,6,4,4,4,6,3,4,3,4,3,6,3,5,4,4,4,7,3,6,5,5,3,4,2,4,4
%N A066102 Number of distinct prime factors of sigma_4(n), the sum of the 4th powers of divisors of n.
%H A066102 Harry J. Smith, <a href="/A066102/b066102.txt">Table of n, a(n) for n=1..1000</a>
%F A066102 a(n) = omega(sigma_4(n)) = A001221(A001159(n)).
%t A066102 Table[PrimeNu[DivisorSigma[4, n]], {n, 1, 50}] (* _G. C. Greubel_, May 08 2017 *)
%o A066102 (PARI) a(n) = { omega(sigma(n, 4)) } \\ _Harry J. Smith_, Nov 14 2009
%Y A066102 Cf. A001159, A001221.
%K A066102 nonn
%O A066102 1,3
%A A066102 _Labos Elemer_, Dec 04 2001