81291

Appears in sequences

• Number of different n X n symmetric matrices with nonnegative entries summing to 4. Also number of symmetric oriented graphs with 4 arcs on n points.at n=21A139594
• Number of length 5 0..n arrays least squares fitting to a zero slope straight line, with a single point taken as having zero slope.at n=19A245135
• Triangle read by rows: T(n,k) is the number of labeled quasi-threshold graphs on vertex set [n] with k components, for n >= 1 and 1 <= k <= n.at n=40A350528