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 A284261 #15 Dec 15 2017 13:02:34
%S A284261 0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,1,0,
%T A284261 0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,
%U A284261 0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,1
%N A284261 a(n) = A284258(n) - A284258(A003961(n)).
%C A284261 The first 2 occurs at n = 429 = 3*11*13. A003961(429) = 1105 = 5*13*17.
%C A284261 The first 3 occurs at n = 7293 = 3*11*13*17. A003961(7293) = 20995 = 5*13*17*19.
%H A284261 Antti Karttunen, <a href="/A284261/b284261.txt">Table of n, a(n) for n = 1..10001</a>
%F A284261 a(n) = A284258(n) - A284258(A003961(n)).
%F A284261 a(n) = A001221(A284254(n)) - A001221(A284254(A003961(n))).
%t A284261 Table[If[n == 1, 0, Subtract @@ Map[Count[#, d_ /; d > First[#]^2] &@ FactorInteger[#][[All, 1]] &, {n, Times @@ Map[#1^#2 & @@ # &, FactorInteger[n] /. {p_, e_} /; e > 0 :> {Prime[PrimePi@ p + 1], e}] - Boole[n == 1]}]], {n, 120}] (* _Michael De Vlieger_, Mar 24 2017 *)
%o A284261 (Scheme) (define (A284261 n) (- (A284258 n) (A284258 (A003961 n))))
%Y A284261 Cf. A001221, A003961, A284254, A284258, A252459.
%K A284261 nonn
%O A284261 1,429
%A A284261 _Antti Karttunen_, Mar 24 2017
%E A284261 Secondary offset corrected by _Antti Karttunen_, Dec 15 2017