A377709 Numbers that have a record number of infinitary divisors that are powerful (A001694).

1, 4, 8, 36, 72, 128, 216, 1152, 3456, 27000, 28800, 86400, 279936, 432000, 4233600, 6998400, 21168000, 34992000, 148176000, 342921600, 1714608000, 8957952000, 12002256000, 197222256000, 207467568000, 438939648000, 1071630000000, 1452272976000, 3072577536000, 7501410000000

Offset

1,2

Comments

Indices of records in A360721.

The corresponding record values are 1, 2, 3, 4, 6, 7, 9, 14, 21, 27, 28, 42, 49, 63, 84, 98, ... (see the link for more values).

Links

Amiram Eldar, Table of n, a(n) for n = 1..117

Amiram Eldar, Table of n, a(n), A360721(a(n)) for n = 1..117

Mathematica

f[p_, e_] := 2^DigitCount[e, 2, 1] - Mod[e, 2]; 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. A001694, A037445, A360721.

Subsequence of A025487.

Sequence in context: A044829 A338086 A033001 * A269012 A149110 A354735

Adjacent sequences: A377706 A377707 A377708 * A377710 A377711 A377712

Keyword

nonn

Author

Amiram Eldar, Nov 04 2024

Status

approved