A069150 Integers of the form k*k!/A062758(k) in the order they appear in A069149, where A062758(k) is the product of squares of divisors of k.

1, 1, 2, 24, 720, 4480, 3628800, 1925, 479001600, 387459072, 20922789888000, 6402373705728000, 5516784599040000, 1124000727777607680000, 135277939046250, 24817936069329577574400, 553211880832106496000000

Offset

1,3

Links

Table of n, a(n) for n=1..17.

Mathematica

Rest[Select[Table[k! k/(Times@@Divisors[k])^2, {k, 30}], IntegerQ]] (* Harvey P. Dale, Oct 17 2020 *)
Select[(# * #! / #^DivisorSigma[0, #]) & /@ Range[1, 30], IntegerQ] (* Amiram Eldar, Jul 16 2022 *)

Prog

(PARI) for(n=1, 30, if((n*(n!))%(n^numdiv(n))==0, print1((n*(n!))/(n^numdiv(n)), ", ")))

Crossrefs

Cf. A062758, A069149.

Sequence in context: A030438 A012723 A354335 * A323491 A046977 A309205

Adjacent sequences: A069147 A069148 A069149 * A069151 A069152 A069153

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 08 2002

Extensions

Name clarified by Amiram Eldar, Jul 16 2022

Missing a(1)=1 inserted by Sean A. Irvine, Apr 06 2024

Status

approved