351650

Appears in sequences

• Triangle T(n,k) of number of labeled directed multigraphs (with loops), without isolated vertices, with n arrows and k vertices (n = 1,2,.., k = 1..2*n).at n=34A120945
• Abundant numbers of the form k^2 + 1.at n=8A178458
• Numbers k of the form p^2 + 1 (for prime p) where k^2 + 1 is also prime.at n=17A235053