15496819560domain: NAppears in sequencesa(n) = Sum_{k=0..2n} (k+1) * A025177(n, k).at n=19A027261Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 1 local maximum.at n=18A159715a(n) = Sum_{k=0..n} k^2 * 2^(n-k) * binomial(n,k).at n=18A383136