A368252 Numbers with a record value of number of uniform divisors (A327527).

1, 2, 4, 6, 12, 24, 30, 60, 120, 180, 210, 420, 840, 1260, 2310, 4620, 9240, 13860, 27720, 30030, 60060, 120120, 180180, 360360, 510510, 1021020, 2042040, 3063060, 6126120, 9699690, 19399380, 38798760, 58198140, 116396280, 223092870, 446185740, 892371480, 1338557220

Offset

1,2

Comments

First differs from A346016 at n = 48, and from A282472 at n = 155.

Links

Amiram Eldar, Table of n, a(n) for n = 1..212

Amiram Eldar, Table of n, a(n), A327527(a(n)) for n = 1..212

Example

The sequence A327527 starts with 1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 5, ... . The record values, 1, 2, 3, 4 and 5, occur at indices 1, 2, 4, 6, 12, the first 5 terms of this sequence.

Mathematica

d[n_] := Module[{e = FactorInteger[n][[;; , 2]]}, 1 + Total[2^Accumulate[Count[e, #] & /@ Range[Max[e], 1, -1]] - 1]]; d[1] = 1;
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. A282472, A327527, A346016.

Subsequence of A025487.

Sequence in context: A168264 A282472 A346016 * A095416 A056795 A141420

Adjacent sequences: A368249 A368250 A368251 * A368253 A368254 A368255

Keyword

nonn

Author

Amiram Eldar, Dec 19 2023

Status

approved