Massive Algorithms: Generate an Alphabetic Sequence

’m looking for a way of generating an alphabetic sequence:

A, B, C, ..., Z, AA, AB, AC, ..., ZZ.

private static String getString(int n) {

    char[] buf = new char[(int) floor(log(25 * (n + 1)) / log(26))];

    for (int i = buf.length - 1; i >= 0; i--) {

        n--;

        buf[i] = (char) ('A' + n % 26);

        n /= 26;

}

    return new String(buf);

}

JDK8

    public static void main(String[] args) {

        int max = 3;

        List<String> alphabet = Seq

            .rangeClosed('A', 'Z')

            .map(Object::toString)

            .toList();

        Seq.rangeClosed(1, max)

           .flatMap(length ->

               Seq.rangeClosed(1, length - 1)

                  .foldLeft(Seq.seq(alphabet), (s, i) -> 

                      s.crossJoin(Seq.seq(alphabet))

                       .map(t -> t.v1 + t.v2)))

           .forEach(System.out::println);

}

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