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 A246661 #21 Feb 04 2022 14:36:37
%S A246661 1,1,1,2,1,1,2,6,1,1,1,2,2,2,6,6,1,1,1,2,1,1,2,6,2,2,2,4,6,6,6,30,1,1,
%T A246661 1,2,1,1,2,6,1,1,1,2,2,2,6,6,2,2,2,4,2,2,4,12,6,6,6,12,6,6,30,20,1,1,
%U A246661 1,2,1,1,2,6,1,1,1,2,2,2,6,6,1,1,1,2,1,1
%N A246661 Run Length Transform of swinging factorials (A056040).
%C A246661 For the definition of the Run Length Transform see A246595.
%H A246661 Alois P. Heinz, <a href="/A246661/b246661.txt">Table of n, a(n) for n = 0..8191</a>
%F A246661 a(2^n-1) = n$ where n$ is the swinging factorial of n, A056040(n).
%t A246661 f[n_] := n!/Quotient[n, 2]!^2; Table[Times @@ (f[Length[#]]&) /@ Select[ Split[ IntegerDigits[n, 2]], #[[1]] == 1&], {n, 0, 85}] (* _Jean-François Alcover_, Jul 11 2017 *)
%o A246661 (Sage) # uses[RLT from A246660]
%o A246661 A246661_list = lambda len: RLT(lambda n: factorial(n)/factorial(n//2)^2, len)
%o A246661 A246661_list(88)
%o A246661 (Python)
%o A246661 # use RLT function from A278159
%o A246661 from math import factorial
%o A246661 def A246661(n): return RLT(n,lambda m: factorial(m)//factorial(m//2)**2) # _Chai Wah Wu_, Feb 04 2022
%Y A246661 Cf. A227349, A246588, A246595, A246596, A246660.
%K A246661 nonn,base
%O A246661 0,4
%A A246661 _Peter Luschny_, Sep 07 2014