A366413 Squarefree composite k such that the smallest nondivisor prime is less than the greatest prime factor, i.e., A053669(k) < A006530(k).

10, 14, 15, 21, 22, 26, 33, 34, 35, 38, 39, 42, 46, 51, 55, 57, 58, 62, 65, 66, 69, 70, 74, 77, 78, 82, 85, 86, 87, 91, 93, 94, 95, 102, 105, 106, 110, 111, 114, 115, 118, 119, 122, 123, 129, 130, 133, 134, 138, 141, 142, 143, 145, 146, 154, 155, 158, 159, 161

Offset: 1

Author

Michael De Vlieger, Jan 07 2024

Keywords

• nonn
• easy

Comments

Squarefree numbers without the empty product, primes, and primorials.

Links

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

Crossrefs

Cf. A000040, A001221, A001222, A002110, A005117, A006530, A053669, A120944.

Programs

Mathematica

s = Select[Range[6, 2^10], And[SquareFreeQ[#], CompositeQ[#] ] &]; Complement[s, Most@ FoldWhileList[Times, 6, Prime@ Range[3, 120], # <= s[[-1]] &] ]

Formula

{a(n)} = { k : Omega(k) = omega(k) > 2, A053669(k) < A006530(k) }.

{a(n)} = { A120944 \ A002110 }.