22a. Fibsum

fibsum

(fibsum n): Sum of Fibonacci numbers 0 through n.

n	(fibsum n)	simplified
0	1	1
1	1+1	2
2	1+1+2	4
3	1+1+2+3	7
4	1+1+2+3+5	12
5	1+1+2+3+5+8	20