Number of nondecreasing integer sequences of length 16 with sum zero and sum of absolute values 2n.

Terms

a(0) =1a(1) =4a(2) =9a(3) =25a(4) =49a(5) =121a(6) =225a(7) =484a(8) =897a(9) =1746a(10) =3062a(11) =5684a(12) =9515a(13) =16498a(14) =27028a(15) =44780a(16) =70648a(17) =113282a(18) =173670a(19) =269204a(20) =403919a(21) =607492a(22) =890300a(23) =1310859a(24) =1881880a(25) =2706891a(26) =3822825a(27) =5395027a(28) =7488282a(29) =10399032