The Italian mathematician Leonardo Fibonacci derived a number series from
calculations concerning the breeding rate of rabbits.
Each pair produces one pair of offspring in the breeding season after their own birth,
and another pair the following season. They then stop breeding.
The Javascript Listing shows that, from the second generation onwards, the number of pairs born,
equals the number born in the previous two generations.
This yields the series 1, 1, 2, 3, 5..., a sequence which also occurs in nature in spiral
growths such as sea shells and the scales of fir cones.
Example :- Number 05 in the Sequence is 8 which is 5 + 3, the two numbers before it.