Number of nondecreasing strings of numbers x(i=1..n) in -7..7 with sum x(i)^3 equal to 0.

Terms

a(0) =1a(1) =8a(2) =8a(3) =38a(4) =42a(5) =148a(6) =202a(7) =552a(8) =890a(9) =2020a(10) =3566a(11) =7176a(12) =12928a(13) =24098a(14) =42656a(15) =75315a(16) =129065a(17) =218078a(18) =360564a(19) =586492a(20) =937076a(21) =1474258a(22) =2283944a(23) =3489536a(24) =5260144a(25) =7831600a(26) =11522100a(27) =16764968a(28) =24136482a(29) =34405442