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Places n where tau(n) + tau(n+2) = tau(2*n+2).
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%I #22 Jan 07 2019 03:50:30

%S 1,3,7,13,15,21,37,43,57,91,103,123,135,147,157,171,177,230,231,235,

%T 242,255,285,331,374,381,387,411,422,451,458,483,501,507,541,547,609,

%U 620,637,667,711,717,781,805,836,860,871,877,884,901,902,907,985,1001,1016,1035,1065,1095,1183,1184,1195

%N Places n where tau(n) + tau(n+2) = tau(2*n+2).

%H G. C. Greubel, <a href="/A192854/b192854.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[1200], DivisorSigma[0, #] +DivisorSigma[0, # + 2] == DivisorSigma[0, 2*# +2] &] (* _G. C. Greubel_, Jan 06 2019 *)

%Y Cf. A000005, A023200, A192690.

%K nonn,less

%O 1,2

%A _Juri-Stepan Gerasimov_, Jul 11 2011