OFFSET
1,1
COMMENTS
This sequence is a subsequence of the abundant numbers A005101.
Includes 2^m*p if p is an odd prime and m >= ceiling(log_2(p+1))-1. - Robert Israel, Dec 28 2017
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(4) = 36 since 36 is larger than 19, which is the sum of its deficient divisors.
MAPLE
filter:= n -> convert(select(d -> numtheory:-sigma(d) < 2*d, numtheory:-divisors(n)), `+`)<n:
select(filter, [$1..1000]); # Robert Israel, Dec 28 2017
MATHEMATICA
totdef[n_] := Total@Select[Divisors@n, DivisorSigma[-1, #] < 2 &];
Select[Range[300], DivisorSigma[-1, #] > 2 && # > totdef[#] &] (* Giovanni Resta, Jan 09 2013 *)
PROG
(PARI) is_A198470(n)=!fordiv(n, d, sigma(d)<2*d & (n-=d)<=0 & return) \\ M. F. Hasler, Jan 11 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Timothy L. Tiffin, Jan 07 2013
EXTENSIONS
More terms from Robert Israel, Dec 28 2017
STATUS
approved