A069934 a(n) = lcm_{d|n} sigma(d).

1, 3, 4, 21, 6, 12, 8, 105, 52, 18, 12, 84, 14, 24, 24, 3255, 18, 156, 20, 126, 32, 36, 24, 420, 186, 42, 520, 168, 30, 72, 32, 9765, 48, 54, 48, 1092, 38, 60, 56, 630, 42, 96, 44, 252, 312, 72, 48, 13020, 456, 558, 72, 294, 54, 1560, 72, 840, 80, 90, 60, 504, 62, 96

Offset: 1

Author

Vladeta Jovovic, Apr 25 2002

Keywords

• mult
• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to lcm's

Crossrefs

Cf. A000203, A051549, A253139.

Programs

Mathematica

Table[LCM@@(DivisorSigma[1,#]&/@Divisors[n]),{n,70}] (* Harvey P. Dale, Feb 22 2023 *)

PARI

A069934(n) = my(d = divisors(n)); lcm(vector(#d, k, sigma(d[k]))); \\ Antti Karttunen, Sep 10 2017

Formula

Multiplicative with a(p^e) = Product_{k=2..e+1} Phi_k(p), where Phi_k(x) is k-th cyclotomic polynomial.