Number of arrays of 4 integers in -n..n with sum zero and equal numbers of elements greater than zero and less than zero.

A201812

Number of arrays of 4 integers in -n..n with sum zero and equal numbers of elements greater than zero and less than zero.

Terms

    a(0) =19a(1) =61a(2) =151a(3) =313a(4) =571a(5) =949a(6) =1471a(7) =2161a(8) =3043a(9) =4141a(10) =5479a(11) =7081a(12) =8971a(13) =11173a(14) =13711a(15) =16609a(16) =19891a(17) =23581a(18) =27703a(19) =32281a(20) =37339a(21) =42901a(22) =48991a(23) =55633a(24) =62851a(25) =70669a(26) =79111a(27) =88201a(28) =97963a(29) =108421

External references