var last = 0
var step = 2500
for (var i = 1; i <= 100*365.25*24*60*60*1000; i += step) {
    j = _DateInterval( i )
    if ( j > last ) {
        console.log( i + ' -> ' + j );
        step = ( j - last ) / 10;
        last = j;
    }
}

function _DateInterval( vv ) {

 ....
}