Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%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 Pérez 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_