■フィボナッチ数列(英: Fibonacci sequence)

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610,
987, 1597, 2584, 4181, 6765, 10946, …

Fn=(1/sqrt(5))(((1+sqrt(5))/2)^n-((1-sqrt(5))/2)^n)