Number of columns in all directed column-convex polyominoes of area n+1.

Terms

a(0) =1a(1) =3a(2) =10a(3) =32a(4) =99a(5) =299a(6) =887a(7) =2595a(8) =7508a(9) =21526a(10) =61251a(11) =173173a(12) =486925a(13) =1362627a(14) =3797374a(15) =10543724a(16) =29180067a(17) =80521055a(18) =221610563a(19) =608468451a(20) =1667040776a(21) =4558234018a(22) =12441155715a(23) =33900136297a(24) =92230468249a(25) =250570010499a(26) =679844574322