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%I #22 Dec 02 2023 09:12:28
%S 1,4,4,21,4,16,4,20,21,16,4,84,4,16,16,65,4,84,4,84,16,16,4,40,21,16,
%T 20,84,4,64,4,48,16,16,16,441,4,16,16,40,4,64,4,84,84,16,4,260,21,84,
%U 16,84,4,40,16,40,16,16,4,336,4,16,84,133,16,64,4,84,16,64,4,420,4,16
%N a(n) = lcm(d(n^3), d(n)), where d(n) = A000005, the number of divisors of n.
%C If n is a product of k distinct primes, then a(n) = 4^k.
%H Antti Karttunen, <a href="/A072696/b072696.txt">Table of n, a(n) for n = 1..16384</a>
%H <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>.
%H <a href="/index/Lc#lcm">Index entries for sequences related to LCM</a>.
%t Table[LCM[DivisorSigma[0, n^3], DivisorSigma[0, n]], {n, 80}] (* _Wesley Ivan Hurt_, Nov 25 2017 *)
%o (PARI) A072696(n) = lcm(numdiv(n),numdiv(n^3)); \\ _Antti Karttunen_, Nov 24 2017
%o (PARI) a(n) = {my(e = factor(n)[,2]); lcm(vecprod(apply(x -> 3*x+1, e)), vecprod(apply(x -> x+1, e)));} \\ _Amiram Eldar_, Dec 02 2023
%Y Cf. A000005, A072695.
%K easy,nonn
%O 1,2
%A _Labos Elemer_, Jul 04 2002
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