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One if odd part of n is 3, zero otherwise.
2

%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