A363333 Numbers with a record number of divisors that are both coreful and bi-unitary.

1, 8, 32, 128, 216, 864, 3456, 7776, 13824, 31104, 108000, 279936, 432000, 972000, 1728000, 3888000, 15552000, 34992000, 62208000, 97200000, 139968000, 248832000, 333396000, 559872000, 592704000, 874800000, 1333584000, 5334336000, 12002256000, 21337344000, 33339600000

Offset

1,2

Comments

Indices of records in A363332.

The corresponding record values are 1, 3, 5, 7, 9, 15, 21, 25, 27, 35, 45, 49, 63, 75, 81, ... (see the link for more values).

Links

Amiram Eldar, Table of n, a(n) for n = 1..261

Amiram Eldar, Table of n, a(n), A363332(a(n)) for n = 1..261

Mathematica

f[p_, e_] := If[OddQ[e], e, e - 1]; d[1] = 1; d[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 120]
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. A363332.

Subsequence of A025487.

Similar sequences: A005934, A293185.

Sequence in context: A269077 A183915 A357789 * A358253 A358252 A374159

Adjacent sequences: A363330 A363331 A363332 * A363334 A363335 A363336

Keyword

nonn

Author

Amiram Eldar, May 28 2023

Status

approved