OFFSET
1,1
COMMENTS
"Least" is required in the definition, otherwise a(14) could be either 2*77636318760 or 5*77636318760, which have the same abundancy. It appears that only a(14) has this property. - T. D. Noe, Jan 24 2010
No other terms through a(800000) have the above property. - Jon E. Schoenfield, Mar 02 2019
LINKS
Jon E. Schoenfield, Table of n, a(n) for n = 1..373
The Prime Glossary, Abundant Numbers
Jon E. Schoenfield, Magma program
Eric Weisstein's World of Mathematics, Abundancy
Xiaolong Wu, A New Type of Abundant Numbers, arXiv:1906.05796 [math.NT], 2019. See Table 1 p. 3.
EXAMPLE
a(4) = 2*2*3*5 = 60 since it has four factors and its abundancy is 2.8, which is greater than that of any other number with four factors; e.g., 2*2*2*2=16, 2*2*2*3=24, 2*2*3*3=36, and 2*3*5*7=210 have abundancies 1.9375, 2.5, 2.52777..., and 2.7428571..., respectively.
PROG
(Magma) // See Schoenfield link.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Sergio Pimentel, Feb 11 2008
EXTENSIONS
Edited by T. D. Noe, Jan 24 2010
Extended by T. D. Noe, Jan 24 2010
a(21)-a(22) from Jon E. Schoenfield, Mar 02 2019
STATUS
approved