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 A102550 #22 May 03 2019 10:44:31
%S A102550 0,1,1,0,1,1,1,0,0,1,1,0,1,1,2,0,1,1,1,0,0,1,1,0,0,1,1,0,1,1,1,0,0,1,
%T A102550 0,0,1,1,1,0,1,1,1,0,1,1,1,0,0,1,2,0,1,1,1,0,0,1,1,0,1,1,2,0,0,1,1,0,
%U A102550 0,1,1,0,1,1,1,0,0,1,1,0,0,1,1,0,2,1,1,0,1,1,0,0,0,1,2,0,1,1,1,0,1,1,1,0,0
%N A102550 Number of distinct prime-factors of n that are bitwise covered by n.
%C A102550 p is bitwise covered by n iff (p = (n AND p)) bitwise: A080099(n,p)=p.
%H A102550 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A102550 a(A102553(n)) = A001221(A102553(n));
%F A102550 a(A102554(n)) < A001221(A102554(n));
%F A102550 a(A102551(n)) = 0, a(A102551(n)) > 0;
%F A102550 a(A102555(n)) = n;
%F A102550 a(m) < n for m < A102555(n).
%F A102550 a(n) = Sum_{p|n} (binomial(n,p) mod 2), where p is a prime. - _Ridouane Oudra_, May 03 2019
%t A102550 a[1] = 0; a[k_] := Module[{f=FactorInteger[k][[;; , 1]]}, Count[BitAnd[k, f]-f, 0]]; Array[a,120] (* _Amiram Eldar_, Feb 06 2019 *)
%Y A102550 Cf. A001221 (omega), A007088, A004676, A080099, A102210.
%Y A102550 Cf. A102551, A102553, A102554, A102555.
%K A102550 nonn
%O A102550 1,15
%A A102550 _Reinhard Zumkeller_, Jan 14 2005
%E A102550 Offset 1 from _Amiram Eldar_, Feb 06 2019