Number of strings of numbers x(i=1..n) in 0..4 with sum i^3*x(i)^2 equal to n^3*16.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =5a(6) =19a(7) =65a(8) =179a(9) =567a(10) =1971a(11) =7188a(12) =24104a(13) =86560a(14) =307758a(15) =1093010a(16) =3680499a(17) =12984253a(18) =44872804a(19) =155894872a(20) =524533909a(21) =1798853267a(22) =6095276268a(23) =20640244000a(24) =68424020576a(25) =228663331673a(26) =756885973017