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

Terms

a(0) =1a(1) =1a(2) =3a(3) =10a(4) =32a(5) =116a(6) =368a(7) =1235a(8) =4321a(9) =13396a(10) =40668a(11) =124627a(12) =362283a(13) =1030513a(14) =2887111a(15) =7874749a(16) =21054468a(17) =55326873a(18) =142607396a(19) =361404953a(20) =901518960a(21) =2213631284a(22) =5356287900a(23) =12780944283a(24) =30087543948a(25) =69923248394a(26) =160510425840