a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0 and a(1) = 11.

Terms

a(0) =0a(1) =11a(2) =12a(3) =24a(4) =37a(5) =62a(6) =100a(7) =163a(8) =264a(9) =428a(10) =693a(11) =1122a(12) =1816a(13) =2939a(14) =4756a(15) =7696a(16) =12453a(17) =20150a(18) =32604a(19) =52755a(20) =85360a(21) =138116a(22) =223477a(23) =361594a(24) =585072a(25) =946667a(26) =1531740a(27) =2478408a(28) =4010149a(29) =6488558