First quadrisection of A140287.

Terms

a(0) =0a(1) =0a(2) =1a(3) =-7a(4) =32a(5) =-120a(6) =401a(7) =-1247a(8) =3712a(9) =-10800a(10) =31201a(11) =-90487a(12) =264992a(13) =-784680a(14) =2345201a(15) =-7051727a(16) =21263872a(17) =-64145760a(18) =193310401a(19) =-581652967a(20) =1747480352a(21) =-5243918040a(22) =15725054801a(23) =-47140982207a(24) =141319714432a(25) =-423717125520