8284926domain: NAppears in sequencesa(n) = Sum_{k=floor((n+2)/2)..n} T(n, k), T given by A026998.at n=21A027009a(n) = Sum_{k=1..n+1} A027960(n+1, n+1+k).at n=20A027974Duplicate of A027974.at n=20A027983