1,1,2,3,5,8,13,21,... acesta este sirul lui Fibonacci
urm numar va fi
13+21=34
1,1,2,3,5,8,13,21,34,
21+34=55
1,1,2,3,5,8,13,21,34,55
34+55=89
1,1,2,3,5,8,13,21,34,55, 89
55+89 = 144
1,1,2,3,5,8,13,21,34,55, 89, 144
144+89 = 233
1,1,2,3,5,8,13,21,34,55, 89, 144, 233
Deci al 13-lea nr e 233
