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Least m such that A(m) = -10^n, where A(n) = sigma(n) - 2n, the abundance of n.
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%I #19 Aug 14 2020 07:59:35

%S 1,11,101,5090,40028,182525,2000006,44244716,400000028,4000000028,

%T 2210000389844,200000000006,2157894737114,160003470403376

%N Least m such that A(m) = -10^n, where A(n) = sigma(n) - 2n, the abundance of n.

%H Jason Earls, <a href="https://pdfs.semanticscholar.org/301f/777cd44aaa90b1a24c2ddc1d07721bbc9051.pdf">Some Smarandache-type sequences and problems concerning abundant and deficient numbers</a>, in Smarandache Notions Journal (2004), Vol. 14.1, pp 265-270.

%t A[m_] := DivisorSigma[1, m]-2*m; Do[m = 1; While[A[m] != -10^n, m++ ]; Print[m], {n, 0, 9}] (* _Ryan Propper_, Oct 01 2006 *)

%K more,nonn

%O 0,2

%A _Jason Earls_, Oct 09 2002

%E More terms from _Ryan Propper_, Oct 01 2006

%E a(10)-a(13) from _Hiroaki Yamanouchi_, Aug 24 2018