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 A121556 Numbers such that sigma(n)^2 is divisible by UnitarySigma(n)*UnitaryPhi(n). 4

%I

%S 1,2,3,6,14,15,30,35,42,70,78,105,190,210,348,357,418,570,714,910,

%T 1045,1144,1254,2090,2296,2730,3135,3432,4060,4522,4674,5278,6270,

%U 6888,10168,10659,10824,12180,12441,13566,14630,15834,16770,17160

%N Numbers such that sigma(n)^2 is divisible by UnitarySigma(n)*UnitaryPhi(n).

%H Donovan Johnson, <a href="/A121556/b121556.txt">Table of n, a(n) for n = 1..1000</a>

%p for n from 1 to 20000 do if numtheory[sigma](n)^2 mod (A047994(n)*A034448(n)) = 0 then printf("%d,",n) ; end if;end do:

%Y Cf. A121647, A078557, A020492, A034448, A047994.

%K nonn

%O 1,2

%A _Yasutoshi Kohmoto_, Sep 12 2006

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Last modified December 5 13:26 EST 2019. Contains 329751 sequences. (Running on oeis4.)