152320

Appears in sequences

• 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=21A080766
• Number of 8-step one space at a time bishop's tours on an n X n board summed over all starting positions.at n=12A187161
• Triangular array read by rows: T(n,k) is the number of size k components in the digraph representation of all functions f:{1,2,...,n}->{1,2,...,n}; n>=1, 1<=k<=n.at n=23A225723
• Sum of the divisors of n^3 - 1.at n=35A234860
• Numbers k such that A122111(k) [conjugated prime factorization of k] is one of Ore's Harmonic numbers (in A001599).at n=19A336317