OFFSET
1,1
COMMENTS
Sequence gives value of sigma(n) for numbers n for which there exists k > n such that A000203(k) = A000203(n) and A007947(k) = A007947(n), where A000203 gives the sum of divisors, and A007947 gives the squarefree kernel of n. The sequence is ordered by the magnitude of n, and contains duplicates, because there are cases of multiple such pairs having the same value of sigma.
The first such duplicate values occur as a(17) = a(22) = 345600 and a(20) = a(25) = 403200.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..6589
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 05 2015
STATUS
approved