What is the explicit rule of this sequence

0-1
1-3
2-7
3-15
4-31
5-63
6-127

(2^[x+1]) - 1


Ex. Term 0 --> (2^[0+1]) - 1 = 2 - 1 = 1
Term 5 --> (2^[5+1]) - 1 = (2^6) - 1 = 64 - 1 = 63

Hope this helps!