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%I #4 Aug 10 2024 15:18:24
%S 12,10924032,16125952,3757637632,45091651584,66563866624,
%T 727145809044307968,1152771972099211264,
%U 845044701535107443245558061611352064
%N Numbers n of the form 2^(A000043-1)*A046528 such that sigma(n) is a perfect number.
%C sigma(sigma(A046528(2,12,13,18,21,22,56,57,175,176,177,..))) is Mersenne prime.
%F a(n)= 2^( A000043(2,5,5,6,7,7,8,8,9,9,9,..)-1)*A046528(2,12,13,18,21,22,56,57,175,176,177,..).
%e 45091651584=2^18*3*7*8191, sigma(45091651584)=137438691328 is perfect number.
%Y Cf. A000396, A000203, A000668, A000043, A046528, A063103.
%K nonn,changed
%O 1,1
%A _Manuel Valdivia_, Oct 12 2010
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