OPTION STRICT: OPTION DEFINT
VAR MAX_G = 4000, MAX_P = 1000000
VAR ROOT_MAX_P = FLOOR(SQR(MAX_P))
VAR HALF_MAX_G = MAX_G DIV 2
VAR G[MAX_G + 1], P[MAX_P + 1]
VAR I, J
CLS: GCLS
P[0] = FALSE: P[1] = 0: P[2] = TRUE
FOR I = 4 TO MAX_P STEP 2 P[I] = FALSE: NEXT
FOR I = 3 TO MAX_P STEP 2 P[I] = TRUE: NEXT
FOR I = 3 TO ROOT_MAX_P STEP 2
  IF P[I] THEN
    FOR J = I * I TO MAX_P STEP I
      P[J] = FALSE
    NEXT
  ENDIF
NEXT
FOR I = 1 TO MAX_G G[I] = 0: NEXT
G[4] = 1 ' 4 is the only sum of 2 even primes
FOR I = 3 TO HALF_MAX_G STEP 2
  IF P[I] THEN
    INC G[I + 1]
    FOR J = I + 2 TO MAX_G - 1
      IF P[J] THEN
        INC G[I + 1]
      ENDIF
    NEXT
  ENDIF
NEXT
VAR C = 0
FOR I = 4 TO 202 STEP 2
  PRINT FORMAT$("%3D", G[I]),
  INC C
  IF C == 10 THEN PRINT: C = 0: ENDIF
NEXT
VAR GM = 0
FOR I = 3 TO MAX_P DIV 2 STEP 2
  IF P[I] THEN
    IF P[MAX_P - I] THEN INC GM: ENDIF
  ENDIF
NEXT
PRINT FORMAT$("G(%D): ", MAX_P); GM
FOR I = 2 TO MAX_G - 10 STEP 10
  FOR J = 1 TO I + 8 STEP 2
    GPSET I DIV 10, 240-G[J],RGB(255,255,255)
  NEXT
NEXT