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%I #13 Nov 08 2017 22:24:20
%S 2,3,8,9,15,26,39,45,74,104,111,117,122,128,146,175,183,195,219,296,
%T 314,333,357,386,471,488,549,554,555,579,584,585,608,626,646,657,794,
%U 831,842,914,915,939,962,1071,1082,1095,1191,1226,1256,1263,1292,1322
%N Numbers n such that 2*phi(n) = phi(2*sigma(n)).
%H Reinhard Zumkeller, <a href="/A260020/b260020.txt">Table of n, a(n) for n = 1..10000</a>
%H S. W. Golomb, <a href="/A006872/a006872_1.pdf">Equality among number-theoretic functions</a>, Unpublished manuscript. (Annotated scanned copy)
%o (Haskell)
%o a260020 n = a260020_list !! (n-1)
%o a260020_list = filter
%o (\x -> 2 * a000010' x == a000010' (2 * a000203' x)) [1..]
%o -- _Reinhard Zumkeller_, Jul 14 2015
%Y Cf. A006872.
%Y Cf. A000010, A000203.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Jul 14 2015