Related to Bernoulli numbers.

Terms

a(0) =1a(1) =5a(2) =26a(3) =97a(4) =265a(5) =362a(6) =-1351a(7) =-13775a(8) =-70226a(9) =-262087a(10) =-716035a(11) =-978122a(12) =3650401a(13) =37220045a(14) =189750626a(15) =708158977a(16) =1934726305a(17) =2642885282a(18) =-9863382151a(19) =-100568547815a(20) =-512706121226