5 ONERRORGOTO1000
10 MODE8:DIM:x=2:c$=CHR$(5)
20 CLS:PRINT"Prime factors (2≤Base<10¹⁰)";:a$=" *"
40 LOCATE0,1:PRINTc$;"Base ?";:INPUT@11;x:LOCATE0,0
45 IFx<2 ORx>=1e10 ORFRACx<>0 THEN40
50 LOCATE0,1:PRINTc$;x;"= .....";
60 u=0:v=0:n=1:t$="":a=x
70 GOTO130
100 u=2:GOSUB500
110 a=a/2
120 IFa-1=0 THEN240
130 IFFRAC(a/2)=0 THEN100
140 b=3
150 c=SQRa+1
160 IFb>=c THEN230
170 IFFRAC(a/b)=0 THEN190
180 b=b+2:GOTO160
190 IFa/b*b-a=0 THEN210
200 GOTO180
210 u=b:GOSUB500
220 a=a/b:GOTO150
230 u=a:GOSUB500
240 a$="":GOSUB530
250 PRINTc$;x;"=";t$;:z$=INPUT$(1,@):GOTO20
500 IFv=u THENn=n+1:GOTO550
520 IFv=0 THEN550
530 IFn>1 THENt$=t$+STR$(v)+"^"+MID$(STR$(n),2)+a$ ELSEt$=t$+STR$(v)+a$
540 n=1
550 v=u:RETURN
1000 IFERR=1 THENCLS:ONERRORGOTO0
1010 IFERL=40 THENRESUME40
1050 LOCATE0,1:PRINTc$;"not found";:z$=INPUT$(1,@):RESUME20