logBinomial :: Int -> Int -> Int
logBinomial n k
  | 0 <= n, n <= _N, 0 <= k, k <= _N = fromIntegral $ P.unsafeIndex (V.unsafeIndex lbin n) k
  | otherwise = error "logBinomial: out of range"
logBinomial :: Int -> Int -> Int
logBinomial n k
  | 0 <= n, n <= _N, 0 <= k, k <= _N = fromIntegral $ P.unsafeIndex (V.unsafeIndex lbin n) k
  | otherwise = error "logBinomial: out of range"
logBinomial n k
  | 0 <= n, n <= _N, 0 <= k, k <= _N = fromIntegral $ P.unsafeIndex (V.unsafeIndex lbin n) k
  | otherwise = error "logBinomial: out of range"