4607296

Appears in sequences

• Triangle read by rows: t(n,m) = Sum_{i=0..n} (-1)^(m-i)*Eulerian1(n-i+1, m-i) *Stirling2(n+i+1, i+1), where Eulerian1 are the Eulerian numbers of the first kind (A173018).at n=27A156364
• Numbers k whose abundance is 20: sigma(k) - 2*k = 20.at n=12A223611
• Numbers k such that sigma(k) == 0 (mod k+10).at n=13A274565