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%I #13 Apr 06 2024 07:53:35
%S 1,2,3,4,7,8,10,14,16,21,22,26,32,44,50,52,63,64,76,92,98,105,110,124,
%T 128,136,152,170,182,184,212,225,230,232,248,256,290,296,310,315,328,
%U 344,370,376,405,410,424,470,472,484,495,512,568,584,592,632,656
%N Deficient numbers k for which sigma(k), the sum of divisors of k, reaches a new maximum.
%C Every power of 2 appears. The deficient number k has sigma(k) < 2*k. In relation to the highly abundant numbers, these numbers might be termed highly deficient numbers.
%H T. D. Noe, <a href="/A240073/b240073.txt">Table of n, a(n) for n = 1..10000</a>
%t t = {}; mn = 0; n = 0; While[Length[t] < 100, n++; d = DivisorSigma[1, n]; If[mn < d < 2*n, AppendTo[t, n]; mn = d]]; t
%o (PARI) lista(kmax) = {my(sigmax = 0, sig); for(k = 1, kmax, sig = sigma(k); if(sig < 2*k && sig > sigmax, sigmax = sig; print1(k, ", ")));} \\ _Amiram Eldar_, Apr 06 2024
%Y Cf. A002093 (highly abundant numbers), A005100 (deficient numbers).
%Y Cf. A228450 (deficient numbers with increasing abundancy).
%K nonn
%O 1,2
%A _T. D. Noe_, Apr 08 2014