27898

Appears in sequences

• Number of permutations p of {1,...,n} such that exactly one element of {p(1),...,p(i-1)} is between p(i) and p(i+1) for all i from 2 to n-1.at n=19A185030
• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.at n=28A227121
• a(n) is the first Zagreb index of the Lucas cube Lambda(n).at n=12A307181
• Triangle read by rows: T(n,k) is the number of sensed combinatorial maps with n edges and k vertices, 1 <= k <= n + 1.at n=31A380615