Number of integer sequences of length n+1 with sum zero and sum of absolute values 8.

Terms

a(0) =2a(1) =24a(2) =162a(3) =780a(4) =2970a(5) =9492a(6) =26474a(7) =66222a(8) =151560a(9) =322190a(10) =643632a(11) =1219374a(12) =2206932a(13) =3838590a(14) =6447660a(15) =10501172a(16) =16639974a(17) =25727292a(18) =38906870a(19) =57671880a(20) =83945862a(21) =120177024a(22) =169447302a(23) =235597650a(24) =323371100a(25) =438575202a(26) =588265524a(27) =780951962a(28) =1026829680