Number of -n..n arrays of 5 elements with adjacent element differences also in -n..n.

Terms

a(0) =99a(1) =1161a(2) =6083a(3) =21141a(4) =57343a(5) =131781a(6) =268983a(7) =502265a(8) =875083a(9) =1442385a(10) =2271963a(11) =3445805a(12) =5061447a(13) =7233325a(14) =10094127a(15) =13796145a(16) =18512627a(17) =24439129a(18) =31794867a(19) =40824069a(20) =51797327a(21) =65012949a(22) =80798311a(23) =99511209a(24) =121541211a(25) =147311009