local mod = 1000000007
local mfl = math.floor

local n, s, k = io.read("*n", "*n", "*n")
local lowlim = mfl(k * n * (n - 1) / 2)
if s < lowlim then
  print(0)
elseif s == lowlim then
  print(1)
else
  s = s - lowlim
  local dp = {}
  for i = 1, s do dp[i] = 0 end
  for i = 1, n do
    local mul = n + 1 - i
    for p = s - mul, 1, -1 do
      local cntlim = mfl((s - p) / mul)
      local dpp = dp[p]
      for j = 1, cntlim do
        local v = j * mul
        dp[p + v] = (dp[p + v] + dpp) % mod
      end
    end
    do
      local cntlim = mfl(s / mul)
      for j = 1, cntlim do
        local v = j * mul
        dp[v] = (dp[v] + 1) % mod
      end
    end
  end
  print(dp[s])
end