Number of distinct grids after n moves in the 4T version of Morpion Solitaire.

Terms

a(0) =1a(1) =5a(2) =107a(3) =1212a(4) =11307a(5) =82008a(6) =492459a(7) =2488802a(8) =10810906a(9) =40954087a(10) =137334461a(11) =412834554a(12) =1123737371a(13) =2789937671a(14) =6354724457a(15) =13348667549a(16) =25978331545a(17) =47005248571a(18) =79292133202a(19) =125052789966a(20) =185063311252a(21) =258100163444a(22) =340693659166a(23) =427231510805a(24) =510573991860