%I #14 Jun 23 2021 02:16:36
%S 0,0,1,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,
%T 0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%U 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0
%N One if odd part of n is 3, zero otherwise.
%C Characteristic function of A007283.
%H Antti Karttunen, <a href="/A099395/b099395.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 G.f.: Sum_{k>=0} x^(3*2^k).
%t Differences[Join[{0,0},Floor[Log[2,2/3 Range[2,130]]]]] (* _Harvey P. Dale_, Mar 01 2012 *)
%o (Scheme) (define (A099395 n) (if (= 3 (A000265 n)) 1 0)) ;; _Antti Karttunen_, Dec 06 2017
%Y First differences of A099396.
%Y Cf. A000265, A007283.
%K nonn
%O 1,1
%A _Ralf Stephan_, Oct 21 2004