1x2x divizibil cu 3
( 1 + x + 2 + x ) divizibil u 3
( 3 + 2x ) divizibil cu 3
2x poate fi = 0, 3, 6, 9, 12, 15, 18, etc.
2x = 6, 12, 18, etc.
x = 3, 6, 9
1323, 1626, 1929
