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a(n) = lcm_{d|n} sigma(d).
11

%I #13 Feb 22 2023 16:34:29

%S 1,3,4,21,6,12,8,105,52,18,12,84,14,24,24,3255,18,156,20,126,32,36,24,

%T 420,186,42,520,168,30,72,32,9765,48,54,48,1092,38,60,56,630,42,96,44,

%U 252,312,72,48,13020,456,558,72,294,54,1560,72,840,80,90,60,504,62,96

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

%H Antti Karttunen, <a href="/A069934/b069934.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>

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

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

%o (PARI) A069934(n) = my(d = divisors(n)); lcm(vector(#d, k, sigma(d[k]))); \\ _Antti Karttunen_, Sep 10 2017

%Y Cf. A000203, A051549, A253139.

%K mult,nonn

%O 1,2

%A _Vladeta Jovovic_, Apr 25 2002