One-half of the sum of one and the square root of five, also called the golden mean, is the limiting ratio of terms of, for ten points, what sequence first derived in 13th century Italy by considering the reproduction of immortal rabbits.
Closely related to the Lucas numbers, it can be found in the sums of the shallow diagonals of Pascal's triangle.  One-half of the sum of one and the square root of five, also called the golden mean, is the limiting ratio of terms of, for ten points, what sequence first derived in 13th century Italy by considering the reproduction of immortal rabbits.
Closely related to the Lucas numbers, it can be found in the sums of the shallow diagonals of Pascal's triangle.  
Fibonacci sequence or numbers