2099520

Appears in sequences

• Triangular array T(n,k) read by rows, giving number of labeled free trees such that the root is smaller than all its children, with respect to the number n of vertices and to the label k of the root.at n=31A071211
• a(n) = Sum_{d|n} phi(n/d)*2^(d+1), with a(0) = 0.at n=20A160619
• Totally multiplicative sequence with a(p) = 9*(p+2) for prime p.at n=23A167310
• Number of endofunctions on [n] where the largest cycle length equals 7.at n=2A246217
• Number of (n+2) X (n+2) 0..2 arrays with nondecreasing sum of every three consecutive values in every row and column.at n=1A250593
• Number of (n+2)X(2+2) 0..2 arrays with nondecreasing sum of every three consecutive values in every row and column.at n=1A250595
• T(n,k)=Number of (n+2)X(k+2) 0..2 arrays with nondecreasing sum of every three consecutive values in every row and column.at n=4A250601
• a(n) = Sum_{d|n} (2^d - (-1)^d)*phi(3*n/d).at n=19A306899