A009262 a(n) = lcm(n, phi(n)).

1, 2, 6, 4, 20, 6, 42, 8, 18, 20, 110, 12, 156, 42, 120, 16, 272, 18, 342, 40, 84, 110, 506, 24, 100, 156, 54, 84, 812, 120, 930, 32, 660, 272, 840, 36, 1332, 342, 312, 80, 1640, 84, 1806, 220, 360, 506, 2162, 48, 294, 100, 1632, 312, 2756, 54, 440, 168, 684, 812, 3422

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

This is a divisibility sequence: if n divides m, a(n) divides a(m). - Franklin T. Adams-Watters, Mar 30 2010

a(n) = n iff n is in A007694.

a(n) is a divisor of A299822(n). It is a proper divisor iff n is in A069209. - Max Alekseyev, Oct 11 2024

Links

• Enrique Pérez Herrero, Table of n, a(n) for n = 1..5000
• Index to divisibility sequences

Crossrefs

Cf. A000010, A007694, A007947, A052106, A069209, A076512, A109395, A174824.

Programs

Maple

with(numtheory); A009262:=n->lcm(n, phi(n)); seq(A009262(n), n=1..100); # Wesley Ivan Hurt, Jan 29 2014

Mathematica

Table[LCM[n, EulerPhi[n]], {n, 100}] (* Wesley Ivan Hurt, Jan 29 2014 *)

PARI

a(n)=lcm(eulerphi(n), n) \\ Charles R Greathouse IV, May 29 2016

Formula

a(n) = A000010(n) * A109395(n) = n * A076512(n) = A299822(n) / gcd(A007947(n),phi(A007947(n))). - Max Alekseyev, Oct 11 2024