OFFSET
1,2
COMMENTS
The asymptotic density of this sequence is Product_{p prime} (1 - 2/p^3) = 0.6768927370... (A340153) (Carlitz, 1932).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Leonard Carlitz, On a problem in additive arithmetic (II), The Quarterly Journal of Mathematics, Vol. os-3, No. 1 (1932), pp. 273-290.
EXAMPLE
1 is a term since both 1 and 2 are cubefree numbers.
7 is not a term since 7+1 = 8 = 2^3 is not cubefree.
MATHEMATICA
cubefreeQ[n_] := Max @ FactorInteger[n][[;; , 2]] < 3; Select[Range[100], cubefreeQ[#] && cubefreeQ[# + 1] &]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Dec 29 2020
STATUS
approved