Number of arrangements of 5 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.

Terms

a(0) =91a(1) =565a(2) =1775a(3) =4201a(4) =8051a(5) =14477a(6) =22583a(7) =34625a(8) =49755a(9) =69749a(10) =91855a(11) =123945a(12) =155779a(13) =197533a(14) =247399a(15) =304785a(16) =361755a(17) =440021a(18) =512415a(19) =611097a(20) =715123a(21) =826765a(22) =936711a(23) =1090865a(24) =1233531a(25) =1393541a(26) =1568623a(27) =1774089a(28) =1955795a(29) =2212029