The sum of the first 100 values of "1,4,7,10,13,16,19,22,25."?

The sum of the first 100 values of "1,4,7,10,13,16,19,22,25."?

an=3n-2
So Sn = 3 * n (n + 1) / 2-2n
Therefore, the sum of the first 100 items is
S100=3*100(100+1)/2-2*100=14950

4, 10, 16, 22 represent the sequence

(number 1) * 6 + 4
4 is the first number
10 is the second number
16 is the third number
22 is the fourth number

Find sequence 1, - 22,3, - 42 ,(-1)^n-1*n2…… The first n terms and?
Find sequence 1, - 2 & # 178;, 3, - 4 & # 178 ,(-1)^n-1*n²…… The first n terms and?

In this form, n should be even
The odd number terms: 1, 3, 5 The sum of these n / 2 terms is very good: the result is S1 = n * n / 4 (the first term plus the last term multiplied by the number of terms divided by 2)
2^2,…… N ^ 2 this n / 2 term, the sum of squares every other term, extract 2 ^ 2. Can become the sum of squares of natural numbers
1,2^2,3^2…… The sum of the first n / 2 items of this sequence is: S2 = n (n / 2 + 1) (2n / 2 + 1) / 12
Then we can calculate the sum of the first n (n must be even) terms of the original sequence: = S1-2 ^ 2s2 = n ^ 2 / 4-N (n + 2) (n + 1) / 6

Fill in 0.1.4.15.64
add

It's 325;
（0+1）*1=1
（1+1）*2=4;
（4+1）*3=15；
（15+1）*4=64；
（64+1）*5=325；

Fill in 41.20.360.108 () according to the rule
Fill in the number according to the rule
4 1.2 0.36 0.108 ( ) ( )
3.48 1.74 0.87 ( ) ( ) 0.10875
1.5 0.75 0.375 ( ) ( )

0.0324 0.00972 0.435 0.2175 0.1875 0.09375

7,47,119,…… The number after 119

3 * 3 = 9,7 * 7 = 49,11 * 11 = 121; 9-2 = 7,49-2 = 47121-2 = 119, so the rule is: an = (4N-1) ^ 2-2, let n = 4, A4 = 15 * 15-2 = 223. In my opinion, this kind of question has no meaning, we can take any integer as the answer, or even "ghosts and snakes": e, PI, LN2, sin1

119, 36, 11, 3, 2, () what do you fill in the brackets?

119、36、11、3、2、（-3)
The middle number * 3 + the last number = the previous number
36*3+11=119
11*3+3=36
3*3+2=11
2*3+x=3
x=-3

119 83 36 47 (). A-37 B11 C-11 D37 which answer to this question

119,83,36,47,（-11） 119-83＝36 83-36＝47 36-47＝-11

323107,35,11,3, () how to solve this sequence

(323-2)/3=107
(107-2)/3=35
(35-2)/3=11
323,107,35,11,3,(1/3 )

What are the rules of the 1 3 2 6 11 19 sequence in the vocational aptitude test

1+3+2=6
3+2+6=11
2+6+11=19
an=a(n-1)+a(n-2)+a(n-3)