417560domain: NAppears in sequencesLeast k such that Sum_{r=n+1..k} r >= n!.at n=13A093000a(n) = floor(sqrt(2*n!)).at n=14A129960Number of permutations p of {1,...,n} such that exactly two elements of {p(1),...,p(i-1)} are between p(i) and p(i+1) for all i from 3 to n-1.at n=26A187817