2246400

Appears in sequences

• An operational recurrence.at n=6A001577
• A unitary phi reciprocal amicable number: consider two different numbers r, s which satisfy the following equation for some integer k: uphi(r) = uphi(s) = (1/k) * r * s / (r-s); or equivalently, 1/uphi(r) = 1/uphi(s) = k * (1/s - 1/r); sequence gives r numbers.at n=30A080766
• a(n) = A002952(n) + A002953(n).at n=19A180277
• Number of even divisors of n!.at n=30A337257