a(n) = 2*A052186(n) - n!.

Terms

a(0) =1a(1) =-1a(2) =0a(3) =0a(4) =4a(5) =34a(6) =274a(7) =2312a(8) =21034a(9) =207790a(10) =2228892a(11) =25890642a(12) =324477994a(13) =4370180744a(14) =63007469346a(15) =968847653702