Ceiling(exp(n)/n^2).

Terms

a(0) =3a(1) =2a(2) =3a(3) =4a(4) =6a(5) =12a(6) =23a(7) =47a(8) =101a(9) =221a(10) =495a(11) =1131a(12) =2618a(13) =6136a(14) =14529a(15) =34712a(16) =83582a(17) =202655a(18) =494411a(19) =1212913a(20) =2990512a(21) =7406845a(22) =18421179a(23) =45988060a(24) =115207839a(25) =289540843a(26) =729832978a(27) =1844715644a(28) =4674594884a(29) =11873860647