OFFSET
1,24
COMMENTS
Sum of divisors of n smaller than n that are abundant numbers (in A005101).
LINKS
FORMULA
EXAMPLE
The proper divisors of 60 are 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. Of these 12, 20 and 30 are in A005101, thus a(60) = 12+20+30 = 62.
MATHEMATICA
a[n_] := DivisorSum[n, # &, # < n && DivisorSigma[1, #] > 2*# &]; Array[a, 100] (* Amiram Eldar, Mar 14 2024 *)
PROG
(PARI) A294889(n) = sumdiv(n, d, (d<n)*(sigma(d)>(2*d))*d);
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 14 2017
STATUS
approved