686826

Appears in sequences

• Triangle T(n,k) = number of forests of labeled rooted trees of height at most 1, with n labels, k of which are used for root nodes and any root may contain >= 1 labels, n >= 0, 0<=k<=n.at n=50A143396
• Number of forests of labeled rooted trees of height at most 1, with n labels, five of which are used for root nodes and any root may contain >= 1 labels.at n=4A273655
• Numbers k such that k^(k + 1) == k + 1 (mod 2*k + 1) while 2*k+1 is not prime.at n=23A380831