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%I #7 Apr 19 2016 01:07:35
%S 8120,8736,8784,19140,11200,21750,8624,15950,8120,8736,8784,19140,
%T 11200,21750,8624,15950,8120,8736,8784,19140,11200,21750,8624,15950,
%U 8120,8736,8784,19140,11200,21750,8624,15950,8120,8736,8784,19140
%N a(1)=2^3*5*7*29=8120; for n>1, a(n) = (-1)sigma(a(n-1)).
%C (-1)sigma is defined in A049060. This is a cyclic sequence whose period is 8, so these numbers are called "(-1)sigma sociable numbers of order 8".
%e The numbers are 2^3*5*7*29, 2^5*3*7*13, 2^4*3^2*61, 2^2*3*5*11*29, 2^6*5^2*7, 2*3*5^3*29, 2^4*7^2*11, 2*5^2*11*29, then repeat.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Feb 14 2008, based on a posting to the Sequence Fans Mailing List by _Yasutoshi Kohmoto_, Feb 02 2005
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