Table of n, a(n) for n=1..10.
If n is even, a(n) is 6 followed by (n - 2) / 2 zeros. If n is odd, a(n) is 3 followed by (n - 1) / 2 zeros.
a(3) = 30. If one types 595 into a calculator and rotates it 180 degrees, they will get 565. 595 - 565 = 30. With a little thought, it is provable that 30 is the smallest possible difference.
Sequence in context: A136939 A136944 A136946 * A211168 A215294 A090932
Adjacent sequences: A125518 A125519 A125520 * A125522 A125523 A125524
Tanya Khovanova and Sergei Bernstein, Dec 29 2006