28109701620domain: NAppears in sequencesa(n) = (2^floor(n+n/2)/sqrt(Pi)^mod(n+1,2))*Gamma(n+1/2)/Gamma(n/2+1).at n=12A264152a(n) = binomial(4*n, 2*n)*(2*n)!/(2^n*n!).at n=6A359761