challenge finite difference

[Quibbler]

What am I doing wrong when I run your program I get
Subscript out of range (I put it up to 50) ...Then
Overflow.
Try mine I've used the data from the link in a data statement.

Code:

CLS
DATA 1,19,143,607,1789,4211,8539
'DATA 5,0,1,20,69,160,305
n = 7
DIM h(10, 10)
FOR i = 1 TO n
READ y(i)
NEXT i
z(1) = y(1)
FOR m = n - 1 TO 1 STEP -1
k = k + 1
diff(k) = z(1)
FOR i = 1 TO m
z(i) = y(i + 1) - y(i)
NEXT i
FOR i2 = 1 TO m
y(i2) = z(i2)
NEXT i2
NEXT m
k = 1
FOR i = 1 TO n
IF i > 2 THEN k = k * (i - 1)
diff(i) = diff(i) / k
IF diff(i) = 0 THEN 10
NEXT i
10 f(1) = 1
FOR j2 = 1 TO i - 3
FOR j1 = 1 TO j2
ff(j1) = ABS(f(j1)) * j2 + ABS(f(j1 + 1))
NEXT j1
FOR j1 = 1 TO j2 + 1
IF j1 MOD 2 = 0 THEN f(j1 + 1) = ff(j1) ELSE f(j1 + 1) = -ff(j1)
h(j2, j1) = f(j1)
NEXT j1
NEXT j2
FOR i8 = 1 TO i
h(0, i8) = 1
NEXT i8
coeff(1) = diff(1)
kk = 1
FOR i8 = 0 TO i - 3
FOR i7 = 1 TO i - 2
x1 = x1 + diff(i7 + 1 + i8) * h(i7 - 1 + i8, i7)
NEXT i7
kk = kk + 1
coeff(kk) = x1
x1 = 0
NEXT i8
FOR g = 1 TO kk
PRINT coeff(g); "x^"; g - 1
NEXT g