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A271504 With a(1) = 1, a(n) is the LCM of all 0 < m < n for which a(m) divides n.

%I A271504 #18 Nov 18 2022 08:32:05
%S A271504 1,1,2,6,2,60,2,210,2,630,2,13860,2,90090,2,90090,2,3063060,2,
%T A271504 29099070,2,29099070,2,1338557220,2,3346393050,2,10039179150,2,
%U A271504 582272390700,2,9025222055850,2,9025222055850,2,18050444111700,2,333933216066450,2,333933216066450
%N A271504 With a(1) = 1, a(n) is the LCM of all 0 < m < n for which a(m) divides n.
%H A271504 Chai Wah Wu, <a href="/A271504/b271504.txt">Table of n, a(n) for n = 1..2309</a> (n = 1..100 from Peter Kagey)
%F A271504 a(2n + 1) = 2 for all n > 1.
%F A271504 a(n) is even for all n > 2.
%t A271504 a = {1}; Do[AppendTo[a, LCM @@ Select[Range[n - 1], Divisible[n, a[[#]]] &]], {n, 2, 40}]; a (* _Michael De Vlieger_, Apr 08 2016 *)
%o A271504 (Python 3.9+)
%o A271504 from math import lcm
%o A271504 from itertools import count, islice
%o A271504 from sympy import divisors
%o A271504 def A271504_gen(): # generator of terms
%o A271504     A271504_dict = {1:1}
%o A271504     yield 1
%o A271504     for n in count(2):
%o A271504         yield (s:=lcm(*(A271504_dict.get(d,1) for d in divisors(n,generator=True))))
%o A271504         A271504_dict[s] = lcm(A271504_dict.get(s,1),n)
%o A271504 A271504_list = list(islice(A271504_gen(),40)) # _Chai Wah Wu_, Nov 17 2022
%Y A271504 Cf. A269347, A271503.
%K A271504 nonn
%O A271504 1,3
%A A271504 _Peter Kagey_, Apr 08 2016