OFFSET
1,1
COMMENTS
The numbers of terms not exceeding 10^k for k = 2, 3, ..., are 1, 2, 7, 72, 719, 7226, 72238, 722565, 7225651, ... Apparently this sequence has an asymptotic density 0.00007225...
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
80 is a term since 80 = 2^4 * 5 and 81 = 3^4 both have a nonsquarefree exponent in their prime factorization.
MATHEMATICA
expSqFQ[n_] := AllTrue[FactorInteger[n][[;; , 2]], SquareFreeQ]; Select[Range[5*10^4], !expSqFQ[#] && !expSqFQ[# + 1] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 04 2021
STATUS
approved