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 A120675 #10 May 11 2017 15:17:09
%S A120675 0,1,1,1,1,1,2,1,1,2,1,1,1,2,2,1,2,1,1,1,2,1,2,2,1,1,2,1,2,1,1,2,1,1,
%T A120675 2,2,1,2,2,2,1,1,1,3,1,1,2,1,2,2,2,1,2,1,2,1,1,2,2,2,1,1,2,1,2,2,1,3,
%U A120675 1,1,2,1,1,2,2,2,1,1,3,1,1,2,2,2,2,1,2,2,2,2,2,1,1,1,3,1,2,2,1,1,2,2,1,2,3
%N A120675 Number of prime factors of odd squarefree numbers A056911.
%C A120675 For n>1, a(n)=1 corresponds to numbers n that are odd primes.
%H A120675 G. C. Greubel, <a href="/A120675/b120675.txt">Table of n, a(n) for n = 1..5000</a>
%F A120675 a(n) = A001221(A056911(n)) = A001222(A056911(n)).
%p A120675 issquarefree := proc(n::integer) local nf, ifa ; nf := op(2,ifactors(n)) ; for ifa from 1 to nops(nf) do if op(2,op(ifa,nf)) >= 2 then RETURN(false) ; fi ; od : RETURN(true) ; end: A001221 := proc(n::integer) RETURN(nops(numtheory[factorset](n))) ; end: A056911 := proc(maxn) local n,a ; a := [1] ; for n from 3 to maxn by 2 do if issquarefree(n) then a := [op(a),n] ; fi ; od : RETURN(a) ; end: A120675 := proc(maxn) local a,n; a := A056911(maxn) ; for n from 1 to nops(a) do a := subsop(n=A001221(a[n]),a) ; od ; RETURN(a) ; end: nmax := 600 : a := A120675(nmax) : for n from 1 to nops(a) do printf("%d,",a[n]) ; od ; amer% # _R. J. Mathar_, Aug 17 2006
%t A120675 PrimeNu[Select[Range[1, 1000, 2], SquareFreeQ]] (* _G. C. Greubel_, May 11 2017 *)
%K A120675 nonn
%O A120675 1,7
%A A120675 _Lekraj Beedassy_, Jun 24 2006
%E A120675 Corrected and extended by _R. J. Mathar_, Aug 17 2006