BASIC BASE 19 to 13 challenge

[AHBAD_ALVIN]

Here's a classic brainteaser for all you people who still want to use basic over ASM...

Let's see who can make a working version first. They win my respect as a maybe-not-as-noobish-BASIC-programmer.
See if you can make a parser that can transorm a string in base 19 numbers (0123456789ABCDEFGHI) and change it into a string in base 13 (0123456789ABC)

It's actually a bit a of a challenge if you haven't tried it before. I suggest using a string full of the base 19 and one of the base 13 characters, and heavy use of the instruction sub()

Good, luck, see who can get it first! (I'll post the answer in 2 days if you guys can't get it)

[nitacku]

[spoiler] Input Str2
length(Str2→Z
"0123456789ABCDEFGHI→Str1
"*→Str3
0
For(X,0,Z-1
Ans+19^X(inString(Str1,sub(Str2,Z-X,1))-1
End
While Ans
Ans/13→Z
sub(Str1,1+round(13fPart(Ans),1),1)+Str3→Str3
int(Z
End
sub(Str3,1,length(Str3)-1
[/spoiler]

*EDIT* 3 bytes smaller. Input is now used.

The routine takes a valid base 19 string via user Input and returns a base 13 string in Ans.
The round() command had to be used to prevent Domain errors due to inaccuracy in the floating point number arithmetic.

This solution most likely does not represent the smallest solution possible, but I believe it to be competitive.
As it currently stands, this solution takes [s]145[/s] 142 bytes of memory by the convention in the rules.

If you don't mind a "*" character in the result, replacing the last line with Str3 will make the routine 130 bytes.

[Weregoose]

[spoiler]Input Str1
13→X
"0123456789ABCDEFGHI→Str2
length(Str1
sum(seq(19^(Ans-X)(inString(Str2,sub(Str1,X,1))-1),X,1,Ans→A
"░
For(B,1,log(AX+1)/log(X
sub(Str2,1+int(round(XfPart(A/X^[escape][/escape])),1)+Ans
End
sub(Ans,1,B-1[/spoiler]
139 bytes. If you don't mind a space character at the end of your result, you can replace the last line with Ans, dropping it down to 131 bytes.

[AHBAD_ALVIN]

I proclaim [s]weregoose[/s] nitaku the winner so far. But can anyone make a SMALLER SCRIPT?

(which looks like it might be hard to do...)

Weregoose is actually in second, cause his is ONE BYTE larger when you make it simpler.

[Weregoose]

I need to create a diversion!

Here are some values for testing for accuracy and the correct number of digits:

[font=courier new]C,D
8G,8H
61B,61C
4323,4324
2G29D,2G29E
1I0DCA,1I0DCB
16696B9,16696BA
H6879GF,H6879GG
BG7E2E9H,BG7E2E9I
8245CGHF5,8245CGHF6

[AHBAD_ALVIN]

mkay, nitacku wont his one. Nice, it actually beat mine (mine was very simular to weregoose's)

kk, you're a not-so-much-noobish-as-the-rest-BASIC-programmer!