OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1500 from Nathaniel Johnston)
EXAMPLE
24 is anti-deficient because its anti-divisors are 7, 16 and their sum is 23 < 24. 26 is deficient because its proper divisors are 1, 2, 13 which sum to 16 and 16 < 26.
MATHEMATICA
q[n_] := Total[Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)]] < n && DivisorSigma[1, n] < 2*n; Select[Range[300], q] (* Amiram Eldar, Jan 13 2022 after Michael De Vlieger at A066417 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, Jul 10 2011
EXTENSIONS
More terms and inserted a(1)=1 from Nathaniel Johnston, Sep 26 2011
STATUS
approved