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A318261 a(n) is the odd part of A318262(n).

%I A318261 #9 Mar 14 2020 05:21:30
%S A318261 3,3,7,5,3,7,15,5,3,7,15,31,9,5,21,3,7,15,31,63,9,21,3,7,15,31,63,127,
%T A318261 17,9,5,21,85,3,51,7,15,31,63,127,255,17,9,73,5,21,85,3,51,7,15,31,63,
%U A318261 127,255,511,33,17,73,5,21,85,341,11,93,3,51,7,15,31
%N A318261 a(n) is the odd part of A318262(n).
%C A318261 The odd part of n is the largest odd divisor of n (A000265).
%H A318261 Peter Luschny, <a href="/A318261/b318261.txt">Table of n, a(n) for n = 1..1000</a>
%o A318261 (Sage)
%o A318261 def A318261_list(len):
%o A318261     count = 0; n = 0; L = []
%o A318261     while count < len:
%o A318261         n += 2
%o A318261         m = power_mod(2, euler_phi(n), n)
%o A318261         if m.is_power_of(2):
%o A318261             v = 2^valuation(n, 2)
%o A318261             L.append(n // v)
%o A318261             count += 1
%o A318261     return L
%o A318261 print(A318261_list(70))
%Y A318261 Cf. A000265, A318262.
%K A318261 nonn
%O A318261 1,1
%A A318261 _Peter Luschny_, Sep 05 2018