ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti tˈuː, pˈæn tʃˈɛŋdɑːŋ ˈɔːlsoʊ mˌeɪd pɹˈɑːɡɹɛs ɪn pɹˈuːvɪŋ ɡˈoʊldbɑːxs kəndʒˈɛktʃɚ baɪ pɹˈuːvɪŋ ðə wˈʌn,fˈaɪv kˈeɪs ˌɪndᵻpˈɛndəntli ænd ðə wˈʌn,fˈoːɹ kˈeɪs ðə fˈɑːloʊɪŋ jˈɪɹ wɪð ˈɛn.bˈiː. bˈɑːɹbən ænd wˈæŋɡ jˈuːən.
In 1962, Pan Chengdong also made progress in proving Goldbach’s conjecture  by proving the (1,5) case independently and the (1,4) case the following year with N.B. Barban and Wang Yuan.