A340373 - OEIS

%I #8 Jan 06 2021 17:49:04

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

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

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

%N a(n) = 1 if n is of the form of 2^i * p^j, with p an odd prime, and i>=0, j>=1, otherwise 0.

%C a(n) = 1 if the odd part of n has exactly one distinct prime divisor, and 0 otherwise.

%H Antti Karttunen, <a href="/A340373/b340373.txt">Table of n, a(n) for n = 1..65537</a>

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

%F a(n) = A069513(A000265(n)).

%F a(n) = [A005087(n) == 1], where [ ] is the Iverson bracket, and A005087(n) = A001221(A000265(n)).

%F a(n) = A340363(n) - A209229(n).

%o (PARI) A340373(n) = (1==omega(n>>valuation(n, 2)));

%Y Cf. A000265, A001221, A005087, A069513, A209229, A340363.

%Y Characteristic function of A336101.

%K nonn

%O 1

%A _Antti Karttunen_, Jan 06 2021