OFFSET
1,1
COMMENTS
Apparently most of the terms are squarefree. Up to 10^13 there are 1150 terms, for only 17 terms k either k or k + 1 is nonsquarefree, and there are no terms k such that both k and k + 1 are nonsquarefree. The first nonsquarefree term is a(32) = 285491549265.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..1150 (terms below 10^13)
EXAMPLE
8857357509 is a term since usigma(8857357509) = 17766604800 > 2 * 8857357509, and usigma(8857357510) = 17851083264 > 2 * 8857357510, where usigma is the sum of unitary divisors function (A034448).
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar and Giovanni Resta, Jan 18 2020
STATUS
approved