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A192275 Super anti-perfect numbers. 0

%I #17 May 04 2019 21:50:36

%S 7,167,507,543,3433,6707,9615,15690,87667,1023971,2054435,5871045,

%T 9150387,14146891,63538839,169623015

%N Super anti-perfect numbers.

%C Like A019279 but using anti-divisors. sigma*^2(n)=sigma*(sigma*(n))=2n, where sigma*(n) is the sum of the anti-divisors of n.

%p for n from 1 do

%p if A066417(A066417(n)) = 2*n then

%p print(n);

%p end if;

%p end do: # _R. J. Mathar_, Oct 02 2011

%Y Cf. A019279, A066417.

%K nonn,more

%O 1,1

%A _Paolo P. Lava_, Jun 28 2011

%E a(9)-a(16) from _Donovan Johnson_, Sep 22 2011

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)