a(n) = round( 1 + e^(n-2) ).

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =21a(5) =56a(6) =149a(7) =404a(8) =1098a(9) =2982a(10) =8104a(11) =22027a(12) =59875a(13) =162756a(14) =442414a(15) =1202605a(16) =3269018a(17) =8886112a(18) =24154954a(19) =65659970a(20) =178482302a(21) =485165196a(22) =1318815735a(23) =3584912847a(24) =9744803447a(25) =26489122131a(26) =72004899338a(27) =195729609430