Question

Ce numar lipseste in sirul dat: 3;7;15;31;127;255

Answer 1

$3,7,15,31,127,255 \\ \\ 3 \times 2 + 1 = 7 \\ \\ 7 \times 2 + 1 = 15 \\ \\ 15 \times 2 + 1 = 31 \\ \\ 31 \times 2 + 1 = 63 \\ \\ 63 \times 2 + 1 = 127 \\ \\ 127 \times 2 + 1 = 255 \\ \\ => \boxed {termen~lipsa=63}$

Answer 2

Lipsește numărul 63
Regula este 2×a+1