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 A025549 #24 Feb 19 2019 23:34:22
%S A025549 1,1,1,1,3,3,3,45,45,45,945,945,4725,42525,42525,42525,1403325,
%T A025549 49116375,49116375,1915538625,1915538625,1915538625,86199238125,
%U A025549 86199238125,603394666875,30773128010625,30773128010625,1692522040584375,96473756313309375,96473756313309375
%N A025549 a(n) = (2n-1)!!/lcm{1,3,5,...,2n-1}.
%H A025549 Michael De Vlieger, <a href="/A025549/b025549.txt">Table of n, a(n) for n = 1..569</a>
%F A025549 a(n) = A001147(n)/A025547(n). - _Michel Marcus_, Dec 02 2014
%p A025549 seq(doublefactorial(2*n-1)/lcm(seq((2*k-1), k=1..n)), n=1..27) ; # _Johannes W. Meijer_, Jun 08 2009
%t A025549 L[ {x___} ] := LCM[ x ]; Table[ (2n-1)!!/L[ Range[ 1, 2n-1, 2 ] ], {n, 1, 50} ]
%t A025549 (* Second program: *)
%t A025549 Array[#!!/LCM @@ Range[1, #, 2] &[2 # - 1] &, 30] (* _Michael De Vlieger_, Feb 19 2019 *)
%o A025549 (PARI) a(n) = (((2*n)!/n!)/2^n)/lcm(vector(n, i, 2*i-1)); \\ _Michel Marcus_, Dec 02 2014
%Y A025549 Not always equal to the second left hand column of A161198 triangle divided by A074599. - _Johannes W. Meijer_, Jun 08 2009
%Y A025549 Cf. A196274 (run lengths of equal terms).
%K A025549 nonn,easy
%O A025549 1,5
%A A025549 _Clark Kimberling_
%E A025549 Description corrected and sequence extended by _Erich Friedman_
%E A025549 More terms from _Michel Marcus_, Dec 02 2014