Egyptian fraction expansion for Pi/4 = arctan(1/2) + arctan(1/3) (Hutton 1776).

Terms

a(0) =2a(1) =3a(2) =-24a(3) =-81a(4) =160a(5) =1215a(6) =-896a(7) =-15309a(8) =4608a(9) =177147a(10) =-22528a(11) =-1948617a(12) =106496a(13) =20726199a(14) =-491520a(15) =-215233605a(16) =2228224a(17) =2195382771a(18) =-9961472a(19) =-22082967873a(20) =44040192a(21) =219667417263a(22) =-192937984a(24) =838860800a(26) =-3623878656