The OP includes a link to an English excerpt written by the author of the "Swing, divide and conquer the factorial" manuscript: http://www.luschny.de/math/fact

The OP includes a link to an English excerpt written by the author of the "Swing, divide and conquer the factorial" manuscript: http://www.luschny.de/math/factorial/SwingIntro.pdf http://www.luschny.de/math/factorial/SwingIntro.pdf