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A365681
Numbers with a record number of exponentially squarefree divisors.
2
1, 2, 4, 6, 12, 24, 36, 60, 120, 180, 360, 840, 1260, 2520, 6300, 7560, 12600, 27720, 69300, 83160, 138600, 332640, 360360, 900900, 1081080, 1801800, 4324320, 5405400, 12612600, 17297280, 18378360, 30630600, 73513440, 86486400, 91891800, 214414200, 294053760
OFFSET
1,2
COMMENTS
Indices of records of A365680.
The corresponding record values are 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 32, 36, 48, 54, 64, 72, 96, ... (see the link for more values).
MATHEMATICA
f[p_, e_] := Count[Range[e], _?SquareFreeQ] + 1; d[1] = 1; d[n_] := Times @@ f @@@ FactorInteger[n]; v = Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {_, _}][[;; , 2]]; seq = {}; dm = 0; Do[If[(dk = d[v[[k]]]) > dm, dm = dk; AppendTo[seq, v[[k]]]], {k, 1, Length[v]}]; seq
CROSSREFS
Cf. A365680.
Subsequence of A025487.
Similar sequences: A306736, A307845, A318278.
Sequence in context: A340637 A362782 A365900 * A377140 A333665 A355595
KEYWORD
nonn
AUTHOR
Amiram Eldar, Sep 15 2023
STATUS
approved