Sum of the site-perimeters of all bargraphs of area n.

Terms

a(0) =0a(1) =4a(2) =12a(3) =30a(4) =72a(5) =166a(6) =376a(7) =837a(8) =1844a(9) =4025a(10) =8723a(11) =18789a(12) =40263a(13) =85892a(14) =182515a(15) =386488a(16) =815890a(17) =1717604a(18) =3606854a(19) =7556995a(20) =15800562a(21) =32974263a(22) =68694801a(23) =142882147a(24) =296749381a(25) =615468930a(26) =1274878193a(27) =2637637046a(28) =5451035408a(29) =11253593442