Number of -n..n arrays of 4 elements with zero sum and no two neighbors summing to zero.

Terms

a(0) =4a(1) =40a(2) =140a(3) =336a(4) =660a(5) =1144a(6) =1820a(7) =2720a(8) =3876a(9) =5320a(10) =7084a(11) =9200a(12) =11700a(13) =14616a(14) =17980a(15) =21824a(16) =26180a(17) =31080a(18) =36556a(19) =42640a(20) =49364a(21) =56760a(22) =64860a(23) =73696a(24) =83300a(25) =93704a(26) =104940a(27) =117040a(28) =130036a(29) =143960