103453402718domain: NAppears in sequencesa(n) = T(n, n-2), T given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=2.at n=28A026587a(n) = Sum_{k=0..2*n-2} T(n,k) * T(n,k+2), with T given by A026584.at n=13A027284