A058251 LCM of n-th primorial number and its Euler totient.

1, 2, 6, 120, 1680, 36960, 5765760, 1568286720, 536354058240, 24672286679040, 2861985254768640, 2661646286934835200, 3545312854197200486400, 5814313080883408797696000, 10500649424075436288638976000

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

a(n) = LCM(A002110(n), A000010(A002110(n)) = LCM(A002110(n), A005867(n)).

a(n) = A009262(A002110(n)). - Michel Marcus, Apr 27 2022

Example

a(6) = LCM(30030,5760) = 5765760.

Maple

[seq(ilcm(product(ithprime(k), k=1..m), product(ithprime(k)-1, k=1..m)), m=1..20)];

Mathematica

LCM[#, EulerPhi[#]]&/@Rest[FoldList[Times, 1, Prime[Range[15]]]] (* Harvey P. Dale, Nov 29 2011 *)

Prog

(PARI) P(n) = prod(k=1, n, prime(k)); \\ A002110
a(n) = my(p= P(n)); lcm(p, eulerphi(p)); \\ Michel Marcus, Apr 27 2022

Crossrefs

Cf. A002110, A000010, A005867, A009262.

Sequence in context: A303441 A075391 A212158 * A180058 A264470 A039716

Adjacent sequences: A058248 A058249 A058250 * A058252 A058253 A058254

Keyword

nonn

Author

Labos Elemer, Dec 05 2000

Extensions

a(0)=1 inserted by Jamie Morken, Apr 27 2022

Status

approved