function index = n_hcomp2index (N)
    if N < 1 then
        N = 1
    end
    m = ceil(N/2)
    index=[0]
    xs=3
    for j = 0:(m-1)
        for i = 0:(m-1)
           x = xs + 3*i
           index = [index round(max(x^2+3/4*j^2,(x-0.5)^2 +3/4*(j+1)^2 ))]
        end
        if modulo(j,3) then 
            xs=xs+1.5 
        else 
            xs=xs-1.5
        end
    end
    index = unique(gsort(index,"g","i"))
    index=index(1:N)
endfunction