What is the number between 0 - 1 3 - 7 () - 31 63 - 127?

What is the number between 0 - 1 3 - 7 () - 31 63 - 127?


fifteen
0+1=1
1+2=3
3+4=7
7+8=15
15+16=31
31+32=63
63+64=127
According to the adjacent different sign of the sign, the number is 15



1, 3, 7, 15, 31, (), 127255 how many are filled in brackets


1,3,7,15,31,(63),127,255
3=1+2
7=3+4
15=7+8
31=15+16
(63)=31+32
127=63+64
255=127+128



What is the nth of 1,3,7,15,31,631272555111023?


The nth power of 2-1