OFFSET
1,1
COMMENTS
EXAMPLE
The sequence starts with a(1) = 12, since 12 is the first imperfect number with abundance greater than 0. Then the next term not yet in the sequence, such that s is not less than 1, is 1.
a(5) is the next abundant number 18, since any deficient number would bring s below 1.
n : 1 2 3 4 5 6 7 8 9 10
a(n): 12 1 2 4 18 3 8 20 10 24
s : 4 3 2 1 4 2 1 3 1 13
PROG
(Python)
from sympy.ntheory import abundance
from itertools import count, filterfalse
def A361206_list(nmax):
A, s = [], 0
for n in range(1, nmax+1):
A2 = set(A)
for y in filterfalse(A2.__contains__, count(1)):
ab = abundance(y)
if ab != 0 and ab + s >= 1:
A.append(y)
s += ab
break
return(A)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
John Tyler Rascoe, Mar 04 2023
STATUS
approved