重複組合せ
H^n_k = \binom{n + k - 1}{k} = \frac{(n + k - 1)!}{k!(n - 1)!}
重複組合せの上下反転
H^n_k = \binom{n + k - 1}{k} = \binom{n + k - 1}{n - 1} = H^k_{n-1}
"Engineer's way of creating knowledge" the English version of my book is now available on [Engineer's way of creating knowledge]
(C)NISHIO Hirokazu / Converted from [Scrapbox] at [Edit]