A game played with two heaps of counters in which a player may take any number from either heap or the same number from both. The player taking the last counter wins.
The th safe combination
is , where , with the golden ratio and the floor
function. It is also true that . The first few safe
combinations are (1, 2), (3, 5), (4, 7), (6, 10), ... (OEIS A000201
and A001950), which are the pairs of elements
from the complementary Beatty sequences for and (Wells 1986, p. 40).