Number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.

A188250

Number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.

Terms

    a(0) =0a(1) =20a(2) =52a(3) =144a(4) =208a(5) =436a(6) =532a(7) =816a(8) =1072a(9) =1508a(10) =1668a(11) =2400a(12) =2592a(13) =3220a(14) =3940a(15) =4768a(16) =5024a(17) =6212a(18) =6500a(19) =7856a(20) =8944a(21) =9988a(22) =10340a(23) =12384a(24) =13280a(25) =14516a(26) =15796a(27) =17824a(28) =18272a(29) =21156

External references