|
%I #9 Mar 30 2012 17:27:13
%S 1,1,1,1,2,2,3,3,48,16,40,40,270,270,945,63,129024,129024,64512,64512,
%T 2016000,96000,528000,528000,144342000,28868400,187644600,20849400,
%U 1787836050,1787836050,59594535,59594535,3999321544458240,121191561953280,1030128276602880
%N a(0) = 1 and a(n) = A180000(n)*a(floor(n/2))^2 for n > 0.
%C lcm(1,2,..,n) = (n!*a(n)) / ((n/2)!*a(n/2))^2.
%C lcm(1,2,..,n)*a(n) is a divisor of n! and n!/(lcm(1,2,..,n)*a(n)) is a square.
%o (Sage)
%o def A205958(n) :
%o if n == 0 : return 1
%o return A180000(n)*A205958(n//2)^2
%Y Cf. A180000, A025527, A205959.
%K nonn
%O 0,5
%A _Peter Luschny_, Feb 04 2012
|
