Number of 0..3 arrays x(0..n-1) of n elements with nondecreasing average value.

Terms

a(0) =4a(1) =10a(2) =23a(3) =51a(4) =110a(5) =233a(6) =488a(7) =1013a(8) =2088a(9) =4278a(10) =8720a(11) =17695a(12) =35768a(13) =72054a(14) =144717a(15) =289887a(16) =579312a(17) =1155257a(18) =2299426a(19) =4568935a(20) =9064316a(21) =17957296a(22) =35529320a(23) =70213565a(24) =138607340a(25) =273351142a(26) =538591471a(27) =1060310343a(28) =2085784818a(29) =4100099321