A377708 Numbers k that have a record number of divisors d such that gcd(d, k/d) is an exponentially odd number (A268335).

1, 2, 4, 6, 12, 24, 36, 60, 120, 180, 360, 840, 1260, 2520, 6300, 7560, 12600, 27720, 69300, 83160, 138600, 360360, 900900, 1081080, 1801800, 5405400, 12612600, 18378360, 30630600, 91891800, 214414200, 349188840, 581981400, 1745944200, 4073869800, 8031343320, 12221609400

Offset

1,2

Comments

First differs from A365681 at n = 22.

First differs from A377140 at n = 95.

Indices of records in A365173.

The corresponding record values are 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 32, 36, 48, 54, ... (see the link for more values).

Links

Amiram Eldar, Table of n, a(n) for n = 1..164

Amiram Eldar, Table of n, a(n), A365173(a(n)) for n = 1..164

Mathematica

f[p_, e_] := Floor[(e + 5)/4] + Floor[(e + 6)/4]; 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. A268335, A365173, A365681, A377140.

Subsequence of A025487.

Sequence in context: A365900 A365681 A377140 * A333665 A355595 A050293

Adjacent sequences: A377705 A377706 A377707 * A377709 A377710 A377711

Keyword

nonn

Author

Amiram Eldar, Nov 04 2024

Status

approved