local mod = 1000000007
local mfl = math.floor

local function bmul(x, y)
  local x0, y0 = x % 31623, y % 31623
  local x1, y1 = mfl(x / 31623), mfl(y / 31623)
  return (x1 * y1 * 14122 + (x1 * y0 + x0 * y1) * 31623 + x0 * y0) % mod
end

local function badd(x, y)
  return (x + y) % mod
end

local function bsub(x, y)
  return x < y and x - y + mod or x - y
end

local function modpow(src, pow)
  local res = 1
  while 0 < pow do
    if pow % 2 == 1 then
      res = bmul(res, src)
      pow = pow - 1
    end
    src = bmul(src, src)
    pow = mfl(pow / 2)
  end
  return res
end

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)
      for j = cntlim, 1, -1 do
        local v = j * mul
        dp[p + v] = badd(dp[p + v], dp[p])
      end
    end
    do
      local cntlim = mfl(s / mul)
      for j = cntlim, 1, -1 do
        local v = j * mul
        dp[v] = badd(dp[v], 1)
      end
    end
  end
  print(dp[s])
end