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

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =1a(5) =10a(6) =15a(7) =26a(8) =91a(9) =180a(10) =375a(11) =1161a(12) =2388a(13) =5361a(14) =14924a(15) =31968a(16) =70100a(17) =183495a(18) =391848a(19) =862189a(20) =2120403a(21) =4548763a(22) =9920865a(23) =23395129a(24) =49909285a(25) =107873523a(26) =245586962a(27) =520810166a(28) =1113291924a(29) =2467392165