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Parity of the Dirichlet inverse of the characteristic function of triangular numbers (A010054).
2

%I #9 Oct 05 2023 18:17:05

%S 1,0,1,0,0,1,0,0,1,1,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,1,0,0,0,0,0,0,

%T 0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,1,0,0,

%U 0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1

%N Parity of the Dirichlet inverse of the characteristic function of triangular numbers (A010054).

%H Antti Karttunen, <a href="/A365799/b365799.txt">Table of n, a(n) for n = 1..101025</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%F a(n) = A000035(A365800(n)).

%o (PARI) A365799(n) = (A365800(n)%2); \\ Uses also code from A365800.

%Y Sequence A365800 reduced modulo 2.

%Y Cf. A000035, A000217, A010054.

%K nonn

%O 1

%A _Antti Karttunen_, Oct 05 2023