Number of arrays of 7 integers in -n..n with sum zero.

Terms

a(0) =1a(1) =393a(2) =8135a(3) =60691a(4) =273127a(5) =908755a(6) =2473325a(7) =5832765a(8) =12354469a(9) =24072133a(10) =43874139a(11) =75715487a(12) =124853275a(13) =198105727a(14) =304134769a(15) =453752153a(16) =660249129a(17) =939749665a(18) =1311587215a(19) =1798705035a(20) =2428080047a(21) =3231170251a(22) =4244385685a(23) =5509582933