MathDB

1

Part of 1998 Junior Balkan MO

Problems(1)

Prove that 111...11222...225 is a perfect square

Source: 0

10/30/2005
Prove that the number 111…11⏟199722…22⏟19985\underbrace{111\ldots 11}_{1997}\underbrace{22\ldots 22}_{1998}5 (which has 1997 of 1-s and 1998 of 2-s) is a perfect square.
inductionPerfect Square