1,2,5,( ),17( )按规律填数

问题描述:

1,2,5,( ),17( )按规律填数

1,2,5,( 10 ),17( 26 )
1 + 1 = 2
2 + 3 = 5
5 + 5 = 10
10 + 7 = 17
17 + 9 = 26