4288306domain: NAppears in sequencesTriangle of Gaussian binomial coefficients [ n,k ] for q = 21.at n=22A022185Triangle of Gaussian binomial coefficients [ n,k ] for q = 21.at n=26A022185a(n) = 111111 in base n.at n=20A053700a(n) = (21^n - 1)/20.at n=6A218724