28 = 1 + 2 + 4 + 7 + 14
28 = (4 + 4)×4 − 4 = 4!+ 4 + 4 - 4
Undergraduate Texts in Mathematics
Graduate Studies in Mathematics
28
28 = 1 + 2 + 4 + 7 + 14
28 = (4 + 4)×4 − 4 = 4!+ 4 + 4 - 4
Undergraduate Texts in Mathematics
Graduate Studies in Mathematics