Circle of circles in a circle......

This is based on a gap of one fifth of the diameter of the circles.  You can try changing the values of the variables in the first five lines of the script. 

var doc = app.activeDocument;
var n = 5;  // number of "parent" circles
var f = 28.346;  // cm to points
var d = 2.54 * f;  // diameter
var g = d / 5;  // gap
var r = d + g;
var m = 0;
var x = doc.width / 2;
var y = - doc.height / 2;
var circle = doc.pathItems.ellipse(y + d / 2, x - d / 2, d, d);
for (var i = 0; i < n; i++) {
    m += 6;
    var polygon = doc.pathItems.polygon(x, y, r, m);
    if (i % 2) {
        polygon.rotate((360 / m) / 2);
    }
    for (var j = 0; j < polygon.pathPoints.length; j++) {
        var top = polygon.pathPoints[j].anchor[1] + d / 2;
        var left = polygon.pathPoints[j].anchor[0] - d / 2;
        var circle = doc.pathItems.ellipse(top, left, d, d);
    }
    polygon.remove();
    r += d + g;
}