Number of nondecreasing integer sequences of length 7 with sum zero and sum of absolute values 2n.

Terms

a(0) =1a(1) =4a(2) =9a(3) =24a(4) =41a(5) =87a(6) =130a(7) =234a(8) =344a(9) =542a(10) =742a(11) =1135a(12) =1477a(13) =2088a(14) =2719a(15) =3676a(16) =4597a(17) =6103a(18) =7462a(19) =9596a(20) =11658a(21) =14568a(22) =17374a(23) =21559a(24) =25287a(25) =30692a(26) =35927a(27) =42952a(28) =49573a(29) =58901