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.

A204540 Numbers k whose basins (as defined in A204539) equal 1.

Original entry on oeis.org

2, 3, 4, 6, 14, 1760, 39046
Offset: 1

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Author

Colm Fagan, Jan 16 2012

Keywords

Comments

Only seven such numbers are known. Referring to A204539, we cannot be certain that these are the only numbers k with the property basin(k) = 1, but there are no others for k less than 12,000,000. Furthermore the average value of basin(k) is approximately equal to k/3 for large values of k, which makes it extremely unlikely that another one will ever be found.
For unknown reasons, all integers > 5 with basin equal to 1 or 2 are even. See A185001 for the list of known numbers with basin = 2.

Crossrefs

Programs

  • Mathematica
    (* First run the program for A204539 to define basin *) Select[Range[1000], basin[#] == 1 &] (* Alonso del Arte, Jan 19 2012 *)