Number of nondecreasing strings of numbers x(i=1..n) in -3..3 with sum x(i)^3 equal to 0.

Terms

a(0) =1a(1) =4a(2) =4a(3) =10a(4) =10a(5) =20a(6) =22a(7) =37a(8) =45a(9) =68a(10) =88a(11) =122a(12) =160a(13) =214a(14) =276a(15) =359a(16) =451a(17) =574a(18) =704a(19) =880a(20) =1066a(21) =1310a(22) =1572a(23) =1899a(24) =2257a(25) =2682a(26) =3158a(27) =3710a(28) =4328a(29) =5038