What kind of chart it is? If it's a line chart, bar chart, area chart, the X values are treated as non-numeric labels. You could place them in a worksheet range, and assign them as the X values of the chart. They will be equally spaced, even though differences in value are not equal.
In an XY chart, you could hide the regular axis labels (keep the tick marks at intervals of 1), add a dummy XY series which has the desired X values, and zero as the Y values so the points are on the bottom of the chart. Hide the points (no markers), then apply data labels using the Category Labels option and Below position.
