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a(n) = lcm(n, phi(n)).
8

%I #29 Oct 12 2024 09:05:24

%S 1,2,6,4,20,6,42,8,18,20,110,12,156,42,120,16,272,18,342,40,84,110,

%T 506,24,100,156,54,84,812,120,930,32,660,272,840,36,1332,342,312,80,

%U 1640,84,1806,220,360,506,2162,48,294,100,1632,312,2756,54,440,168,684,812,3422

%N a(n) = lcm(n, phi(n)).

%C This is a divisibility sequence: if n divides m, a(n) divides a(m). - _Franklin T. Adams-Watters_, Mar 30 2010

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

%C a(n) is a divisor of A299822(n). It is a proper divisor iff n is in A069209. - _Max Alekseyev_, Oct 11 2024

%H Enrique PĂ©rez Herrero, <a href="/A009262/b009262.txt">Table of n, a(n) for n = 1..5000</a>

%H <a href="/index/Di#divseq">Index to divisibility sequences</a>

%F a(n) = A000010(n) * A109395(n) = n * A076512(n) = A299822(n) / gcd(A007947(n),phi(A007947(n))). - _Max Alekseyev_, Oct 11 2024

%p with(numtheory); A009262:=n->lcm(n, phi(n)); seq(A009262(n), n=1..100); # _Wesley Ivan Hurt_, Jan 29 2014

%t Table[LCM[n, EulerPhi[n]], {n, 100}] (* _Wesley Ivan Hurt_, Jan 29 2014 *)

%o (PARI) a(n)=lcm(eulerphi(n), n) \\ _Charles R Greathouse IV_, May 29 2016

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

%K nonn

%O 1,2

%A _David W. Wilson_