%I #20 Dec 02 2017 06:10:26
%S 0,0,0,0,0,0,1,0,1,0,1,0,1,1,0,0,0,1,1,0,1,1,0,0,0,1,0,1,0,0,1,0,0,0,
%T 1,1,1,1,0,0,1,1,0,1,0,0,1,0,0,0,0,1,0,0,1,1,0,0,1,0,1,1,0,0,0,0,1,0,
%U 1,1,0,1,1,1,0,1,0,0,1,0,0,1,0,1,0,0,1,1,0,0,1,0,1,1,0,0,1,0,0,0,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0
%N a(n) = (A000120(n) + A000203(n)) mod 2.
%C Characteristic function of A295299.
%H Antti Karttunen, <a href="/A295297/b295297.txt">Table of n, a(n) for n = 1..65537</a>
%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F a(n) = A000035(A000120(n) + A000203(n)).
%F a(n) = A010060(n) XOR A053866(n), where XOR is a bitwise-XOR (A003987).
%F a(n) = A294898(n) mod 2 = A294899(n) mod 2.
%F a(n) = A295875(A156552(n)). - _Antti Karttunen_, Dec 02 2017
%t Array[Mod[DivisorSigma[1, #] + DigitCount[#, 2, 1], 2] &, 120] (* _Michael De Vlieger_, Nov 26 2017 *)
%o (Scheme) (define (A295297 n) (A000035 (+ (A000203 n) (A000120 n))))
%o (PARI) a(n) = (hammingweight(n) + sigma(n)) % 2; \\ _Michel Marcus_, Dec 02 2017
%Y Cf. A295298 (positions of zeros), A295299 (of nonzeros).
%Y Cf. A003987, A000120, A000203, A010060, A053866, A294898, A294899, A295296, A295875.
%K nonn
%O 1
%A _Antti Karttunen_, Nov 26 2017