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%I #10 Mar 05 2020 03:40:42
%S 3,4,105,165,195,2205,2835,38805,131145,407925,936495,1025505,1231425,
%T 1276905,1788255,1925565,2521695,2792145,2847585,3289935,5003745,
%U 5295885,5710089,6315309,6986889,13496385,17168085,19210065,20171385,22348365,26879685,27798705
%N Solutions k of the equation cototient(k) = cototient(k-1) + cototient(k-2) where cototient(k) is A051953.
%H Amiram Eldar, <a href="/A332972/b332972.txt">Table of n, a(n) for n = 1..176</a>
%e 3 is a term since cototient(3) = 1 and cototient(1) + cototient(2) = 0 + 1 = 1.
%e 105 is a term since cototient(105) = 57 and cototient(103) + cototient(104) = 1 + 56 = 57.
%t cotot[n_] := n - EulerPhi[n]; Select[Range[3, 10^6], cotot[#] == cotot[# - 1] + cotot[# - 2] &]
%Y Cf. A051953, A065557, A065900, A075565, A076136, A076251, A145469, A291126, A291176, A292033, A294995.
%K nonn
%O 1,1
%A _Amiram Eldar_, Mar 04 2020
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