Number of strings of numbers x(i=1..n) in 0..3 with sum i^3*x(i)^2 equal to n^3*9.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =5a(6) =4a(7) =18a(8) =52a(9) =84a(10) =243a(11) =844a(12) =2265a(13) =6462a(14) =15993a(15) =52222a(16) =136310a(17) =389017a(18) =998916a(19) =2953402a(20) =7916043a(21) =21798836a(22) =57115869a(23) =161252708a(24) =426637798a(25) =1149156169a(26) =3004327516a(27) =8128762648a(28) =21242600043