OFFSET
1,2
COMMENTS
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.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
MATHEMATICA
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
PROG
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Apr 08 2014
STATUS
approved