Number of subsets of {-n..n} whose sum of reciprocals is 1.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =48a(6) =96a(7) =192a(8) =384a(9) =768a(10) =1536a(11) =5632a(12) =11264a(13) =22528a(14) =77312a(15) =154624a(16) =309248a(17) =922624a(18) =1845248a(19) =6848512a(20) =17096576a(21) =34193152a(22) =68386304a(23) =272849152a(24) =545698304a(25) =1091396608a(26) =2182793216a(27) =8290181120a(28) =16580362240a(29) =65667289088