1251584

Appears in sequences

• Number of permutations of 2 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.at n=9A190824
• Triangle read by rows: T(n,k) = number of linear chord diagrams with n chords such that every chord has length at least k (1 <= k <= n).at n=39A293157
• a(1) = 1; thereafter a(n) is the smallest number > a(n-1) which is neither of the form 2*a(i) nor Sum_{j=1..n-1} ( b_j*a(j) ) where 0 < i < n, b_j = 0 or 1.at n=24A331800