How can I scatter plot every other nth cell?

[kfirbep]

I have huge amount of data and I need to scatter plot every 20th cell, I was wondering how can I do it? I have (Plotting a graph with every nth cell) found here a solution by using the code =INDEX($A$4:$A$38,ROW(A1)*7) that someone suggested there but I have a little problem.
The first line I need to use is line 22, then after this line I need every 20th cell. can someone help me? I am a newbie in excel so I don't even know how to read this code right. all I did was to change it to =index($D$22:D25739,Row(D22)20
but it doesn't work...
thank you in advance

 

[JGordon11]

Book1
	A	B	C	D	E	F	G	H
1	Data		Every	3	Every	5	Every	7
2	17		17		17		17
3	13		7		15		22
4	23		1		18		4
5	7		11		12		10
6	21		19		3
7	15		12
8	1		24
9	22		10
10	14
11	11
12	18
13	6
14	19
15	9
16	4
17	12
18	20
19	16
20	24
21	2
22	3
23	10
24	8
25	5
26
Sheet3

Cell Formulas
Range	Formula
C2:C9	C2	=INDEX(A2:A25, SEQUENCE(ROUNDUP(ROWS(A2:A25)/D1,0),,1,D1))
E2:E6	E2	=INDEX(A2:A25, SEQUENCE(ROUNDUP(ROWS(A2:A25)/F1,0),,1,F1))
G2:G5	G2	=INDEX(A2:A25, SEQUENCE(ROUNDUP(ROWS(A2:A25)/H1,0),,1,H1))
Dynamic array formulas.