OFFSET
1,1
COMMENTS
This sequence is different from A112643. The two sequences agree for the first 50 terms but differ thereafter. The exceptions, i.e. those odd unitary abundant numbers that are not squarefree ordinary abundant numbers, are in A129486.
22309287 is the smallest term not divisible by 5. 33426748355 is the smallest term not divisible by 3. - Donovan Johnson, May 15 2013
The numbers of terms not exceeding 10^k, for k = 5, 6, ..., are 34, 137, 1714, 16918, 181744, 1752337, 17290556, ... . Apparently, the asymptotic density of this sequence exists and equals 0.00017... . - Amiram Eldar, Sep 02 2022
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Unitary Divisor.
FORMULA
EXAMPLE
The third odd unitary abundant number is 21945. Hence a(3) = 21945.
MAPLE
# see A034683 for the code of isA034683()
isA129485 := proc(n)
type(n, 'odd') and isA034683(n) ;
end proc:
for n from 1 do
if isA129485(n) then
print(n);
end if;
end do: # R. J. Mathar, Nov 10 2014
MATHEMATICA
UnitaryDivisors[n_Integer?Positive]:=Select[Divisors[n], GCD[ #, n/# ]==1&]; sstar[n_]:=Plus@@UnitaryDivisors[n]-n; Select[Range[1, 10^5, 2], sstar[ # ]># &]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Ant King, Apr 17 2007
STATUS
approved