From a sequence of integers (a,b,c,d) each of the sequences
(c, d, a, b), (b, a, d, c), (a + nc, b + nd, c, d), (a + nb, b, c + nd, d)
for arbitrary integer n can be obtained by one step. Is it possible to obtain (3,4,5,7) from (1,2,3,4) through a sequence of such steps? number theory proposednumber theory