OFFSET
1,1
COMMENTS
In other words, numbers n such that sigma(x) = n has at least two distinct solutions, with each x having the same squarefree kernel, where sigma(x) is the sum of divisor function (A000203).
FORMULA
EXAMPLE
4800 is the sum of divisors of 1512 and 2058, and rad(1512) = rad(2058) = 42, hence 4800 is in the sequence with j=1512 and k=2058.
KEYWORD
nonn
AUTHOR
Naohiro Nomoto, Jan 23 2015
EXTENSIONS
More terms from Antti Karttunen, Apr 13 2015
STATUS
approved