This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A145643 #24 Sep 07 2024 08:54:06
%S A145643 1,2,3,1,15,6,105,6,35,60,385,90,5005,1260,75075,315,1276275,210,
%T A145643 24249225,525,509233725,11550,11712375675,34650,2342475135,900900,
%U A145643 2342475135,3153150,67931778915,28028,2105885146365,14014,2573859623335
%N A145643 Cubefree part of n!!.
%H A145643 Chai Wah Wu, <a href="/A145643/b145643.txt">Table of n, a(n) for n = 1..500</a>
%F A145643 a(n) = A050985(A006882(n)). - _Michel Marcus_, May 11 2020
%t A145643 CubefreePart[n_Integer?Positive] := Times @@ Power @@@ ({#[[1]], Mod[ #[[2]], 3]} & /@ FactorInteger[n]); Table[CubefreePart[n!! ], {n, 1, 40}]
%o A145643 (Python)
%o A145643 from sympy import factorint, prod
%o A145643 def A145643(n):
%o A145643 return 1 if n <= 1 else prod(p**(e % 3) for p, e in factorint(prod(range(n,0,-2))).items())
%o A145643 # _Chai Wah Wu_, Feb 04 2015
%o A145643 (PARI) a(n) = my(f = factor(prod(i = 0, (n-1)\2, n - 2*i))); prod(i = 1, #f~, f[i, 1]^(f[i, 2] % 3)); \\ _Amiram Eldar_, Sep 07 2024
%Y A145643 Cf. A004709, A050985, A006882, A069705 (cubefree part of 2^n), A145642.
%K A145643 nonn
%O A145643 1,2
%A A145643 _Artur Jasinski_, Oct 15 2008