A058251 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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: A075391 A376378 A212158 * A180058 A376866 A264470

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