{"author_name":"inamori","type":"rich","width":"100%","provider_name":"Hatena Blog","description":"Problem 63 http://projecteuler.net/index.php?section=problems&id=63 9\u307e\u3067\u3067\u8003\u3048\u308c\u3070\u3088\u3044\u3002 num_digits n = length (takeWhile (>0) a) where a = n:[ div n 10 | n <- a ] count d = length (takeWhile (\\(e,n) -> n == e) [ (e, num_digits (d^e)) | e <- [1..] ]) main = print (sum (map count [1..9])) Problem 64 http://pr\u2026","url":"https://inamori.hateblo.jp/entry/20100226/p2","categories":["Haskell"],"blog_title":"inamori\u2019s diary","provider_url":"https://hatena.blog","published":"2010-02-26 00:00:01","blog_url":"https://inamori.hateblo.jp/","title":"Project Euler 63,64","height":"190","version":"1.0","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Finamori.hateblo.jp%2Fentry%2F20100226%2Fp2\" title=\"Project Euler 63,64 - inamori\u2019s diary\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","image_url":null,"author_url":"https://blog.hatena.ne.jp/inamori/"}