Row sums of an unsigned characteristic triangle for the Fibonacci numbers.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =31a(5) =80a(6) =209a(7) =546a(8) =1429a(9) =3740a(10) =9791a(11) =25632a(12) =67105a(13) =175682a(14) =459941a(15) =1204140a(16) =3152479a(17) =8253296a(18) =21607409a(19) =56568930a(20) =148099381a(21) =387729212a(22) =1015088255a(23) =2657535552a(24) =6957518401a(25) =18215019650a(26) =47687540549a(27) =124847601996