$$CH_3-C(CH_3)_2-CH(C_2H_5)-CH_2-CH_2-CH_2-CH_2-CH_3$$
$$CH_3-CH(CH_3)-CH_2-CH_2-CH(CH_3)-CH_3$$
$$CH_3-CH_2-CH_2-CH_2-CH_3$$
$$CH_3-CH(CH_3)-CH(CH_3)-CH(CH_3)-CH_3$$
$$CH_3-CH_2-CH(C_2H_5)-CH_2-CH_2-CH_2-CH_3$$
$$CH_3-CH(CH_3)-CH(CH_3)-CH_3$$