A086132 Numbers that have the same largest prime factor as their arithmetic derivative.

4, 9, 16, 25, 27, 49, 50, 54, 81, 108, 121, 125, 144, 169, 196, 225, 242, 256, 289, 343, 361, 392, 400, 432, 441, 500, 529, 578, 605, 625, 676, 729, 784, 841, 847, 961, 972, 1014, 1029, 1058, 1083, 1089, 1183, 1225, 1323, 1331, 1369, 1372, 1444, 1445, 1452

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

q[n_] := Module[{f = FactorInteger[n]}, FactorInteger[n * Plus @@ ((Last[#] / First[#]) & /@ f)][[-1, 1]] == f[[-1, 1]]]; Select[Range[2, 1500], q] (* Amiram Eldar, Jul 12 2024 *)

Crossrefs

Cf. A003415, A006530.

Sequence in context: A292675 A254719 A266918 * A010433 A175592 A331219

Adjacent sequences: A086129 A086130 A086131 * A086133 A086134 A086135

Keyword

nonn

Author

Labos Elemer, Jul 23 2003

Status

approved