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a(n) = (A000120(n) + A000203(n)) mod 2.
10

%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