This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A051547 #32 Jan 05 2025 19:51:36
%S A051547 1,1,2,2,4,4,12,12,12,12,60,60,60,60,120,120,240,240,720,720,720,720,
%T A051547 7920,7920,7920,7920,7920,7920,55440,55440,55440,55440,55440,55440,
%U A051547 55440,55440,55440,55440,55440,55440,55440,55440,55440,55440,55440,55440,1275120,1275120,1275120
%N A051547 a(n) = lcm{ phi(1), ..., phi(n) }, where phi is Euler's totient function A000010.
%H A051547 Michael De Vlieger, <a href="/A051547/b051547.txt">Table of n, a(n) for n = 1..10000</a>
%H A051547 P. Moree, H. Roskam, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/33-4/moree.pdf">On an arithmetical function related to Euler's totient and the discriminator</a>, Fib. Quart. 33 (1995) 332-340.
%t A051547 FoldList[LCM @@ {#1, EulerPhi@ #2} &, Range@ 44] (* _Michael De Vlieger_, Dec 09 2018 *)
%o A051547 (PARI) a(n) = lcm(vector(n, k, eulerphi(k))); \\ _Michel Marcus_, Jul 30 2017
%o A051547 (PARI) apply( A051547(n)=lcm(apply(eulerphi,[2..n])), [1..50]) \\ Defines the function A051547; apply(...) for check & example. - _M. F. Hasler_, Dec 09 2018
%Y A051547 Cf. A000010, A076244 (distinct values), A076245 (n where a(n) > a(n-1)).
%K A051547 nonn
%O A051547 1,3
%A A051547 _N. J. A. Sloane_