Predict the next

Ravi went buying clothes at the mall and he saw a bunch of shirts with the $N$ flower petals printed on them , all of the shirts were arranged in a row with the first shirt starting with $0$ petals printed and the second with only $1$ petal from there on the next shirt had the $N$ of petals where $N$ is equal to the sum of $N$ for the previous two shirts i.e for the third shirt $N_2$ = $N_0$ + $N_