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

1,1

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

Formula

Set difference of A005117 and A002110.

Mathematica

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

Crossrefs

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

Sequence in context: A340787 A286607 A204827 * A168252 A071561 A241561

Adjacent sequences: A366879 A366880 A366881 * A366883 A366884 A366885

Keyword

nonn,easy

Author

Michael De Vlieger, Feb 08 2024

Status

approved