PRINT
PRINT "＜ラグランジュの４平方の定理＞"
PRINT "    すべての自然数は４つの平方数の和で表すことができる。"
PRINT
DIM Q(500)
LET w=1
FOR a=0 TO 8
   FOR b=a TO 8
      FOR c=b TO 8
         FOR d=c TO 8
            LET Q(w)=a^2+b^2+c^2+d^2
            IF Q(w)=75 THEN
               PRINT "    75  = ";a;"^ 2 + ";b;"^ 2 + ";c;"^ 2 + ";d;"^ 2"
            END IF
            LET w=w+1
         NEXT d
      NEXT c
   NEXT b
NEXT a
PRINT
PRINT 
CALL sort(Q,w)
LET R=10
FOR i=1 TO w
   IF Q(i)>100 THEN GOTO 10
   IF Q(i)=R THEN
      PRINT
      LET R=R+10
   END IF
   PRINT Q(i);
10 NEXT i
   PRINT
END

EXTERNAL SUB sort(a(),m)
   FOR i=1 TO m-1
      FOR j=i+1 TO m
         IF a(i)>a(j) THEN
            LET t=a(j) 
            LET a(j)=a(i)
            LET a(i)=t
         END IF
      NEXT j
   NEXT i
END SUB