Produced by Thomas Papanikolaou See also: Catalan's Constant [Ramanujan's] PG#682 The algorithm used is the one presented by Greg Fee on ISSAC '90 (using only integer arithmetic in the main loop). Again, I have verified the previous 1000100-digit value using LiDIA and text comparison. Best Thomas Papanikolaou Catalan constant to 1500000 digits computed on October 26, 1996 by using a Sun Sparc20 in 7 day 7 hour 14 min 52 sec 71 hsec The algorithm used is the standard series for Catalan, accelerated by an Euler transform as shown by Greg Fee, ACM 1990, Proceedings of the ISAAC conference, 1990, p. 157 The algorithm was implemented using the LiDIA library for computational number theory and it will be part of the multiprecision floating-point arithmetic of the package in release 1.4. LiDIA is available from ftp://crypt1.cs.uni-sb.de/pub/systems/LiDIA/LiDIA-1.2.1.tgz http://www-jb.cs.uni-sb.de/LiDIA/linkhtml/lidia/lidia.html Here is the output of the program: Calculating Catalan's constant to 1500000 decimals Time required: 7 day 7 hour 14 min 52 sec 71 hsec Catalan = .91596559417721901505460351493238411077414937428167213426649811962176301977625\ 476947935651292611510624857442261919619957903589880332585905943159473748115840\ 699533202877331946051903872747816408786590902470648415216300022872764094238825\ 995774150881639747025248201156070764488380787337048990086477511322599713434074\ 854075532307685653357680958352602193823239508007206803557610482357339423191498\ 298361899770690364041808621794110191753274314997823397610551224779530324875371\ 878665828082360570225594194818097535097113157126158042427236364398500173828759\ 779765306837009298087388749561089365977194096872684444166804621624339864838916\ 280448281506273022742073884311722182721904722558705319086857354234985394983099\ 191159673884645086151524996242370437451777372351775440708538464401321748392999\ 947572446199754961975870640074748707014909376788730458699798606448749746438720\ 623851371239273630499850353922392878797906336440323547845358519277777872709060\ 830319943013323167124761587097924554791190921262018548039639342434956537596739\ 494354730014385180705051250748861328564129344959502298722983162894816461622573\ 989476231819542006607188142759497559958983637303767533853381354503127681724011\ 814072153468831683568168639327293677586673925839540618033387830687064901433486\ 017298106992179956530958187157911553956036689036990493966753843775810493189955\ 385516262196253316804016273752130120940604538795076053827123197467900882369178\ 615573389124417223833938148120775994298491724397668575632718068808279982979378\ 849432724934657607490543874819526813074437046294635892810276531705076547974494\ 839948959477092788591195848724127866084088554597823812492260505610094584486698\ 958576871611171786662336847409949385541321093755281815525881591502228244454441\ 718609946588151766496078223678970519269711312571375454370124329673057246845015\