131725440domain: NAppears in sequences(n-1)-st elementary symmetric function of {1,1,2,2,3,3,4,4,5,5,...,Floor[(n+1)/2]}.at n=13A203151Triangle read by rows. The coefficients of the polynomials hypergeom([-x, -x, -n], [-x - n, -x - n], 1) * Product_{j=1..n} (j + x)^2 in ascending order of powers.at n=29A358502