First differences of A175111.

Terms

a(0) =1a(1) =120a(2) =1442a(3) =6840a(4) =21122a(5) =51000a(6) =105122a(7) =194040a(8) =330242a(9) =528120a(10) =804002a(11) =1176120a(12) =1664642a(13) =2291640a(14) =3081122a(15) =4059000a(16) =5253122a(17) =6693240a(18) =8411042a(19) =10440120a(20) =12816002a(21) =15576120a(22) =18759842a(23) =22408440a(24) =26565122a(25) =31275000a(26) =36585122