{"description":"def isPentagonal(q): x = (1 + math.sqrt(1 + 24 * q)) / 6.0 return int(x) == x def isTriagonal(q): x = (1 + math.sqrt(1 + 8 * q)) / 2.0 return int(x) == x","version":"1.0","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fsucrose.hatenablog.com%2Fentry%2F20110527%2Fp2\" title=\"\u3042\u308b\u6570\u304c\u4e09\u89d2\u6570\u3084\u4e94\u89d2\u6570\u304b\u5224\u5b9a - \u552f\u7269\u662f\u771f @Scaled_Wurm\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","blog_url":"https://sucrose.hatenablog.com/","type":"rich","provider_url":"https://hatena.blog","blog_title":"\u552f\u7269\u662f\u771f @Scaled_Wurm","image_url":null,"title":"\u3042\u308b\u6570\u304c\u4e09\u89d2\u6570\u3084\u4e94\u89d2\u6570\u304b\u5224\u5b9a","author_url":"https://blog.hatena.ne.jp/sucrose/","width":"100%","published":"2011-05-27 00:00:01","provider_name":"Hatena Blog","url":"https://sucrose.hatenablog.com/entry/20110527/p2","height":"190","categories":["euler"],"author_name":"sucrose"}