Signed partitions of n into n parts in {-n..n}\{0}.

Terms

a(0) =1a(1) =1a(2) =5a(3) =17a(4) =78a(5) =375a(6) =1919a(7) =10144a(8) =55189a(9) =306632a(10) =1734019a(11) =9948977a(12) =57790152a(13) =339241199a(14) =2009749140a(15) =12002162624a(16) =72186635028a(17) =436913179401