Number of nonzero coefficients of order n in Baker-Campbell-Hausdorff expansion.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =8a(5) =7a(6) =32a(7) =31a(8) =96a(9) =97a(10) =512a(11) =511a(12) =2048a(13) =2047a(14) =7396a(15) =7531a(16) =32768a(17) =32767a(18) =131072a(19) =131071a(20) =508436a(21) =512245a(22) =2097152a(23) =2097151a(24) =8202208a(25) =8207797a(26) =33256980a(27) =33335611a(28) =134217728a(29) =134217727