OFFSET
1,2
COMMENTS
Numbers n such that usigma(x) = n has more solutions x than any smaller n, where usigma(x) is the sum of unitary divisors of x (A034448).
The unitary version of A145899.
The corresponding number of solutions for each term is: 1, 2, 3, 4, 6, 7, 11, 18, 27, 30, 32, 48, 63, 65, 71, 88, 89, 102, 121, 122, 131, 144, 188, 190, 203, 262, 313, 364, 377, 472, 483, 584, 668, 725, 810, 928, 1076, 1138.
Is this a subsequence of A025487? - David A. Corneth, Jun 25 2017
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..53
EXAMPLE
There are 3 solutions to usigma(x) = 24: usigma(14) = usigma(15) = usigma(23) = 24. For all m < 24, there are 2 or fewer solutions to usigma(x) = m, thus 24 is in the sequence.
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jun 25 2017
STATUS
approved