A051547 a(n) = lcm{ phi(1), ..., phi(n) }, where phi is Euler's totient function A000010.

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

Michael De Vlieger, Table of n, a(n) for n = 1..10000

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

Adjacent sequences: A051544 A051545 A051546 * A051548 A051549 A051550

Keyword

nonn

Author

N. J. A. Sloane

Status

approved