Variable Sequence Problem

[theblmamba]

Hello All,
I need to breakdown an algorithm on pen and paper, but I am having trouble with it since it is not an arithmetic sequence problem. I broke down the pattern but still I am having trouble coming up with an algorithm for it. Can anybody please help.
Thank you!

 

[WhiteCube]

1: 01
2: 0223
3: 024345
4: 02464567
5: 0246856789

Split every line.

1: 0     1
2: 02    23
3: 024   345
4: 0246  4567
5: 02468 56789

2n-2 gives 0,2,4,6,8

2n-1 gives 1,3,5,7,9

REM BASIC demonstration
FOR N=1 TO 5
 S=""
 A=(2*N)-2
 B=(2*N)-1
 FOR I=0 TO A STEP 2
  S+=STR(I)
 NEXT
 FOR I=N TO B STEP 1
  S+=STR(I)
 NEXT
 ? N;" ";S
NEXT

 

[theblmamba]

WhiteCube you are awesome!!! The question really confused me because it said executing an algorithm which I thought there was one algorithm; however, seeing your answer it makes much sense!!!
Thank you!!