cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A365783 a(n) = squarefree kernel of A126706(n).

Original entry on oeis.org

6, 6, 10, 6, 14, 6, 10, 22, 15, 6, 10, 26, 6, 14, 30, 21, 34, 6, 15, 38, 10, 42, 22, 30, 46, 6, 14, 33, 10, 26, 6, 14, 58, 39, 30, 62, 42, 66, 15, 34, 70, 6, 21, 74, 30, 38, 51, 78, 10, 6, 82, 42, 57, 86, 35, 22, 30, 46, 94, 21, 6, 14, 66, 10, 102, 69, 26, 106
Offset: 1

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Author

Michael De Vlieger, Sep 19 2023

Keywords

Comments

Terms are squarefree and composite, i.e., in A120944.

Examples

			Let b(n) = A126706(n) and let squarefree kernel rad(n) = A007947(n).
a(1) = 6 = rad(b(1)) = rad(12).
a(2) = 6 = rad(b(2)) = rad(18).
a(3) = 10 = rad(b(3)) = rad(20), etc.
		

Crossrefs

Programs

  • Mathematica
    Map[Times @@ FactorInteger[#][[All, 1]] &, Select[Range[12, 212], Nor[PrimePowerQ[#], SquareFreeQ[#]] &] ]
  • PARI
    apply(x->(x/factorback(factorint(x)[, 1])), select(x->(!issquarefree(x) && !isprimepower(x)), [1..1000])) \\ Michel Marcus, Sep 19 2023

Formula

a(n) = A007947(A126706(n)).