MathDB
Is it true ??

Source: Bulgaria TST 2003 P4

September 8, 2012
number theory proposednumber theory

Problem Statement

Is it true that for any permulation a1,a2.....,a2002a_1,a_2.....,a_{2002} of 1,2....,20021,2....,2002 there are positive integers m,nm,n of the same parity such that 0<m<n<20030<m<n<2003 and am+an=2am+n2a_m+a_n=2a_{\frac {m+n}{2}}