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 A181183 #17 Jan 08 2023 09:35:27 %S A181183 1,1,1,0,1,1,1,1,0,1,1,0,1,1,1,0,1,0,1,0,1,1,1,1,0,1,1,0,1,1,1,0,1,1, %T A181183 1,1,1,1,1,1,1,1,1,0,0,1,1,0,0,0,1,0,1,1,1,1,1,1,1,0,1,1,0,0,1,1,1,0, %U A181183 1,1,1,0,1,1,0,0,1,1,1,0,0,1,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,0,0,1,1,1,1,1,1 %N A181183 a(n) = sigma(tau(n)) (mod 2). %H A181183 Antti Karttunen, <a href="/A181183/b181183.txt">Table of n, a(n) for n = 1..65537</a> %H A181183 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a> %H A181183 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a> %F A181183 a(n) = A000035(A062069(n)). - _Antti Karttunen_, Nov 18 2017 %p A181183 A181183:= n-> (numtheory[sigma](numtheory[tau](n)) mod 2): %p A181183 seq (A181183(n), n=1..105); %t A181183 Array[Mod[DivisorSigma[1, DivisorSigma[0, #]], 2] &, 105] (* _Michael De Vlieger_, Nov 18 2017 *) %o A181183 (PARI) A181183(n) = (sigma(numdiv(n))%2); \\ _Antti Karttunen_, Nov 18 2017 %Y A181183 Cf. A000035, A062069. %K A181183 nonn %O A181183 1,1 %A A181183 _Jani Melik_, Jan 26 2011