a>2
2a+1=P1+P2+P3
2a=(P1+P2+P3)-1
P is prime numbers.a>2
2a+1=O1+O2+O3
2a=(O1+O2+O3)-1
O is odd numbers.For example,
2a=6 (a=3)
6=(3+2+2)-1 This is prime numbers.
6=(3+3+1)-1=(5+1+1)-1 This is odd numbers.
2a=8 (a=4)
8=(5+2+2)-1=(3+3+3)-1 This is prime numbers.
8=(7+1+1)-1=(5+3+1)-1=(3+3+3)-1 This is odd numbers.
2a=10 (a=5)
10=(7+2+2)-1=(5+3+3)-1 This is prime numbers.
10=(5+5+1)-1=(7+3+1)-1=(9+1+1)-1=(5+3+3)-1 This is odd numbers.
∴ (P1+P2+P3)-1⊂(O1+O2+O3)-1⊂2a
Therefore, Goldbach's weak conjecture is correct.