prob.js

const { random, floor } = Math;
function tryit() {
	let count = 0;
	while (true) {
		++count;
		if (random() < 1 / (2000 - count)) {
			return count;
		}
	}
}


let data = [];

for (let ii = 0; ii < 10000; ++ii) {
	let num_rolls = tryit();
	let bucket = floor(num_rolls / 200);
	data[bucket] = (data[bucket] || 0) + 1;
}

for (let ii = 0; ii < data.length; ++ii) {
	console.log(`${ii*200}-${(ii+1)*200}: ${data[ii] || 0}`);
}