漏れも作ってみた。

public class NumberPyramid {
    public static void main(String[] args) {
        int maxHeight = Integer.parseInt(args[0]); // NumberFormatException は放置
        StringBuffer[] row = new StringBuffer[maxHeight]; // 各行の内容を保持
        int value = 0;

        // 各行を作成
        for (int curHeight = 0; curHeight < maxHeight; curHeight++) {
            row[curHeight] = new StringBuffer();
            for (int i = 0; i <= curHeight; i++) {
                row[curHeight].append(" ");
                row[curHeight].append(++value);
            }
        }
(つづく)