A051549 a(n) = LCM { sigma(1), ..., sigma(n) }.

1, 1, 3, 12, 84, 84, 84, 168, 840, 10920, 32760, 32760, 32760, 32760, 32760, 32760, 1015560, 1015560, 1015560, 1015560, 1015560, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 4062240, 12186720

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000203.

Programs

Maple

a:= proc(n) option remember; `if`(n=0, 1,
       ilcm(a(n-1), numtheory[sigma](n)))
    end:
seq(a(n), n=0..35);  # Alois P. Heinz, Dec 11 2024

Mathematica

nn=40;With[{sig=DivisorSigma[1,Range[nn]]},Table[LCM@@Take[sig,n],{n,nn}]] (* Harvey P. Dale, Nov 15 2013 *)

Extensions

a(0)=1 inserted by Alois P. Heinz, Dec 11 2024