lTry this:
lsumup(m, n) = m > n ? 0 : 1./m + sumup(m+1, n);
lsumdown(m, n) = m > n ? 0 : 1./n +
sumdown(m, n-1);
ltest(n) = sumup(1, n) == sumdown(1,
n);
lmap(test, range(1, 100));
l[1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1,
1, 0, 0, 0, 0, 1, 0, 1,
1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1,
1, 1, 0, 1, 0, 0, 1,
1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0,
0, 1, 1, 1, 1, 1, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 1, 0]
lGrouping sensitivity is due to round-off error.