The Eta triangle.

Terms

a(0) =-1a(1) =-11a(2) =2a(3) =-114a(4) =29a(5) =-2a(6) =-3963a(7) =1156a(8) =-122a(9) =4a(10) =-104745a(11) =32863a(12) =-4206a(13) =222a(14) =-4a(15) =-3926745a(16) =1287813a(17) =-184279a(18) =12198a(19) =-366a(20) =4a(21) =-198491580a(22) =67029582a(23) =-10317484a(24) =781981a(25) =-30132a(26) =562a(27) =-4