Related to Genocchi numbers.

Terms

a(0) =2a(1) =5a(2) =7a(3) =-26a(4) =-265a(5) =-1351a(6) =-5042a(7) =-13775a(8) =-18817a(9) =70226a(10) =716035a(11) =3650401a(12) =13623482a(13) =37220045a(14) =50843527a(15) =-189750626a(16) =-1934726305a(17) =-9863382151a(18) =-36810643322a(19) =-100568547815a(20) =-137379191137a(21) =512706121226