login
A051547
a(n) = lcm{ phi(1), ..., phi(n) }, where phi is Euler's totient function A000010.
4
1, 1, 2, 2, 4, 4, 12, 12, 12, 12, 60, 60, 60, 60, 120, 120, 240, 240, 720, 720, 720, 720, 7920, 7920, 7920, 7920, 7920, 7920, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 55440, 1275120, 1275120, 1275120
OFFSET
1,3
LINKS
P. Moree, H. Roskam, On an arithmetical function related to Euler's totient and the discriminator, Fib. Quart. 33 (1995) 332-340.
MATHEMATICA
FoldList[LCM @@ {#1, EulerPhi@ #2} &, Range@ 44] (* Michael De Vlieger, Dec 09 2018 *)
PROG
(PARI) a(n) = lcm(vector(n, k, eulerphi(k))); \\ Michel Marcus, Jul 30 2017
(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
CROSSREFS
Cf. A000010, A076244 (distinct values), A076245 (n where a(n) > a(n-1)).
Sequence in context: A138317 A103659 A069947 * A330719 A095329 A327486
KEYWORD
nonn
STATUS
approved