You can see hidoku puzzles 1 to 6 on my blog. I created the solution to this puzzle using a C program which I wrote myself. The puzzle was made by trial and error with the help of a Python program written by Rainhard Findling. I produced the image you can see below and double-checked for a unique solution here.

Fill in the empty squares in the grid above. When you have finished, it must contain each of the numbers 1 through 64 exactly once and each number must appear horizontally, vertically or diagonally adjacent to the numbers immediately above or below it numerically.

See answer