These are called Borwein integrals named after David and Jonathan Borwein, father-and-son mathematicians who first introduced them in 2001. If you extrapolate you will find that when you add the next obvious factor sinc(x/15) this sequence fails. 😕 pic.twitter.com/Tl5iMR0mlL
— Fermat's Library (@fermatslibrary) July 28, 2019