A009286 a(n) = lcm(sigma(n), phi(n)).

1, 3, 4, 14, 12, 12, 24, 60, 78, 36, 60, 28, 84, 24, 24, 248, 144, 78, 180, 168, 96, 180, 264, 120, 620, 84, 360, 168, 420, 72, 480, 1008, 240, 432, 48, 1092, 684, 180, 168, 720, 840, 96, 924, 420, 312, 792, 1104, 496, 798, 1860, 288, 1176, 1404, 360, 360, 120, 720, 1260

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to lcm's

Crossrefs

Cf. A000010, A000203, A009223, A062354, A084921.

Programs

PARI

A009286(n) = lcm(sigma(n), eulerphi(n)); \\ Antti Karttunen, May 26 2017

Formula

From Antti Karttunen, May 26 2017: (Start)

a(n) = A062354(n) / A009223(n).

a(A000040(n)) = A084921(n). - after Enrique Pérez Herrero's May 17 2012 comment in the latter sequence.

(End)