There are n steps: n = 2a+1n = 3b+2n = 5c+4n = 6d+5n = 7e, where a, b, c, d and e are integers. If n+ 1 becomes: n+ 1=2a+2 can be divisible by 2; N+ 1=3b+3 is divisible by 3; N+ 1=5c+5 is divisible by 5; N+ 1=6d+6 is divisible by 6. K is an integer > n = 730k-1= 7e30 * (k+3)-91= 7 * (e+13)-9130 * (k+3) = 7 * (e