A361460 - OEIS

%I #12 Mar 14 2023 18:31:42

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

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

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

%N a(n) = 1 if A135504(n+1) = 2 * A135504(n), otherwise 0.

%H Antti Karttunen, <a href="/A361460/b361460.txt">Table of n, a(n) for n = 1..100000</a>

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

%F a(n) = 1 if A135504(n) is a multiple of n+1, otherwise 0.

%F a(n) = [A135506(n) = 1], where [ ] is the Iverson bracket.

%F a(n) = 1 if A135506(n) is not prime, otherwise 0. [Conjectured]

%o (PARI)

%o up_to = 65537;

%o A135506list(up_to_n) = { my(v=vector(up_to), x1=1, x2); for(n=2, 1+up_to_n, x2 = x1+lcm(x1, n); v[n-1] = (x2/x1)-1; x1=x2); (v); };

%o v135506 = A135506list(up_to);

%o A135506(n) = v135506[n];

%o A361460(n) = (1==A135506(n));

%o (PARI)

%o A361460list(up_to_n) = { my(v=vector(up_to), x1=1, x2); for(n=2, 1+up_to_n, x2 = x1+lcm(x1, n); v[n-1] = !(x1%n); x1=x2); (v); };

%o v361460 = A361460list(up_to);

%o A361460(n) = v361460[n];

%Y Characteristic function of A361461.

%Y Cf. A135504, A135506, A361463.

%K nonn

%O 1

%A _Antti Karttunen_, Mar 13 2023