A366882 Squarefree numbers that are not primorials.

3, 5, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 46, 47, 51, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 102, 103, 105, 106, 107, 109, 110

Offset: 1

Author

Michael De Vlieger, Feb 08 2024

Keywords

• nonn
• easy

Comments

Squarefree k such that the smallest nondivisor prime is less than the greatest prime factor, i.e., A053669(k) < A006530(k).

Contains odd primes.

Superset of A366413.

The number 42 is here but missing from A087246.

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002110, A005117, A006530, A053669, A087246, A366413.

Programs

Mathematica

With[{s = 6}, Complement[Select[Range[Max[#] ], SquareFreeQ], #] &@ FoldList[Times, 1, Prime@ Range[s] ] ]

Formula

Set difference of A005117 and A002110.