The sum of the areas of the bargraphs of semiperimeter n (n>=2).

Terms

a(0) =1a(1) =4a(2) =16a(3) =60a(4) =218a(5) =778a(6) =2744a(7) =9600a(8) =33391a(9) =115638a(10) =399137a(11) =1374050a(12) =4720272a(13) =16187632a(14) =55434424a(15) =189607406a(16) =647872199a(17) =2211794804a(18) =7545239986a(19) =25722676402a(20) =87641357150a(21) =298456587038