A335386 Tri-unitary highly composite numbers: where the number of tri-unitary divisors (A335385) increases to a record.

1, 2, 6, 24, 120, 840, 7560, 83160, 1081080, 18378360, 349188840, 8031343320, 200783583000, 5822723907000, 180504441117000, 6678664321329000, 273825237174489000, 11774485198503027000, 553400804329642269000, 27116639412152471181000, 1437181888844080972593000

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..32

Formula

A335385(a(n)) = 2^(n-1).

Mathematica

f[p_, e_] := If[e == 3 || e == 6, 4, 2]; d[1] = 1; d[n_] := Times @@ (f @@@ FactorInteger[n]); dm = 0; s = {}; Do[If[(d1 = d[n]) > dm, dm = d1; AppendTo[s, n]], {n, 1, 1100000}]; s

Crossrefs

Analogous sequences: A002182 (highly composite), A002110 (unitary), A037992 (infinitary), A293185 (bi-unitary), A318278 (exponential), A306736 (exponential infinitary), A307845 (exponential unitary), A309141 (nonunitary), A322484 (semi-unitary).

Cf. A335385.

Sequence in context: A334395 A347064 A037992 * A114779 A317681 A230363

Adjacent sequences: A335383 A335384 A335385 * A335387 A335388 A335389

Keyword

nonn

Author

Amiram Eldar, Jun 04 2020

Status

approved