Number of columns of length 1 in all bargraphs of semiperimeter n (n>=2).

Terms

a(0) =1a(1) =2a(2) =5a(3) =14a(4) =40a(5) =116a(6) =341a(7) =1014a(8) =3045a(9) =9222a(10) =28137a(11) =86408a(12) =266887a(13) =828560a(14) =2584111a(15) =8092646a(16) =25438494a(17) =80235386a(18) =253854855a(19) =805447478a(20) =2562252423a(21) =8170557076a(22) =26112495767a(23) =83626191936a(24) =268331079046a(25) =862537758650