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