194426

Appears in sequences

• 2-nadirs of sigma: numbers k such that sigma(k-2) > sigma(k-1) > sigma(k) < sigma(k+1) < sigma(k+2).at n=9A076774
• Maximum number of nonempty subtrees of a binary tree with n leaves.at n=13A092781
• Maximum possible number of subtrees of an n-node unrooted tree in which each node has maximum degree three (equivalently, rooted binary trees in which some internal nodes may have only one child). A subtree is a nonempty contiguous set of nodes, not necessarily including all descendants of the root.at n=27A124454
• a(n) is the position of the first occurrence of 2n as a local minimum in the prime gaps (A001223).at n=16A286711
• a(n) = (n^4-3*n^2+4*n+2)/2.at n=25A387525