Maximal possible numerator for a sum of the form 1 +/- 1/2 +/- 1/3 +/- ... +/- 1/n.

Terms

a(0) =1a(1) =3a(2) =11a(3) =25a(4) =137a(5) =127a(6) =949a(7) =2003a(8) =7129a(9) =7381a(10) =83711a(11) =86021a(12) =1145993a(13) =1171733a(14) =1195757a(15) =2436559a(16) =42142223a(17) =41461543a(18) =800021557a(19) =788381929a(20) =799467289a(21) =810048769a(22) =18863914247a(23) =19087007117a(24) =99182995801a(25) =100212655201a(26) =312536252003a(27) =315404588903