INPUT PROMPT "初項？ ":a
INPUT PROMPT "公差？ ":b
INPUT PROMPT "何項まで表示？ ":n
PRINT
CALL TASU(a,b,n)
PRINT
END

EXTERNAL SUB TASU(x,y,m)
DO WHILE m>0
   PRINT "  ";x;
   LET x=x+y
   LET m=m-1
   CALL TASU(x,y,m)
LOOP
END SUB