A377140 -id:A377140 - cp's OEIS frontend

A377139 Numbers that have more cubefree divisors than any smaller number.

1, 2, 4, 6, 12, 30, 36, 60, 180, 420, 900, 1260, 4620, 6300, 13860, 44100, 60060, 69300, 180180, 485100, 900900, 3063060, 6306300, 15315300, 58198140, 107207100, 290990700, 1179278100, 1338557220, 2036934900, 6692786100, 22406283900, 38818159380, 46849502700, 194090796900

Offset: 1

Amiram Eldar, Oct 17 2024

nonn

First differ from A333931 and A353899 at n = 17.
Indices of records in A073184.
The corresponding record values are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 27, 36, 48, 54, 72, 81, 96, 108, ... (see the link for more values).

Amiram Eldar, Table of n, a(n) for n = 1..140
Amiram Eldar, Table of n, a(n), A073184(a(n)) for n = 1..140

Subsequence of A004709 and A025487.

Cf. A004709, A073184, A333931, A353899, A377140.

f[p_, e_] := If[e == 1, 2, 3]; d[1] = 1; d[n_] := Times @@ f @@@ FactorInteger[n]; With[{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]

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

Original entry on oeis.org

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

Amiram Eldar, Nov 04 2024

nonn

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).

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

Cf. A268335, A365173, A365681, A377140.

Subsequence of A025487.

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

cp's OEIS Frontend

A377139 Numbers that have more cubefree divisors than any smaller number.

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