set talk off
clea
s=28
dimen a[s]
a[1]=3
a[2]=4
a[3]=5
for n=4 to s
a[n]=a[n-1]+a[n-2]+a[n-3]
endfor
"第28項是",a[s]
set talk on
如果要求任意項,用下邊的：
set talk off
input "請輸入項數(shù)："to s
if s