4, -2, 10,-14, 34-62, … What's the eighth number?

The eighth number is 254, and the process is as follows:

2=2*4-6

10=2*2+6

14=2* 10-6

34= 14*2+6

62=2*34-6

130=2*62+6

254=2* 130-6

The absolute values of pairwise numerical differences are: 6, 12, 24, 48 and 96 respectively.

So we can push back192,384.

The seventh number is-130, and the eighth number is 254.

Extended data:

Recursive series classification

According to whether the number of terms is limited, it can be divided into finite series and infinite series.

1 and a series with a limited number of items is a "finite series".

2. A sequence with infinite terms is an infinite sequence.

Some special sequences

1, a series with periodic changes is called a periodic series (such as trigonometric function);

2. A series with equal terms is called a constant series. (Note that constant series is a special case of increasing series and decreasing series. )

Baidu Encyclopedia-Recursive Series (Series Name)