Number of nondecreasing integer sequences of length 8 with sum zero and sum of absolute values 2n.

Terms

a(0) =1a(1) =4a(2) =9a(3) =25a(4) =46a(5) =103a(6) =163a(7) =307a(8) =478a(9) =791a(10) =1143a(11) =1818a(12) =2495a(13) =3663a(14) =4994a(15) =7002a(16) =9154a(17) =12532a(18) =15986a(19) =21200a(20) =26726a(21) =34398a(22) =42532a(23) =54145a(24) =65791a(25) =81872a(26) =98871a(27) =121163a(28) =144174a(29) =175083