D.2.2.7 fibonacci

Procedure from library general.lib (see general_lib).

Usage:

fibonacci(n); n,p integers

Return:

fibonacci(n): nth Fibonacci number, f(0)=f(1)=1, f(i+1)=f(i-1)+f(i)
- computed in characteristic 0, of type string
fibonacci(n,p): f(n) computed in characteristic 0 or prime(p)
- of type number if a basering is present and p=0=char(basering) or if prime(p)=char(basering)
- of type string else

Example:

LIB "general.lib";
fibonacci(42); "";             //f(42) of type string (as long integer)
→ 267914296
→ 
ring r = 2,x,dp;
number b = fibonacci(42,2);    //f(42) of type number, computed in r
b;
→ 0

See also: prime.