Calculates the number of balls stacker in the shape of a triangular pyramid given the number of layers

BallsInPyramid.py

def count_layer(layer):
    """ Returns the number of balls in a layer """
    if layer == 0:
        return 0
    else:
        return count_layer(layer-1) + layer

def count_pyramid(numLayers):
    currentLayer = 0
    numBalls = 0 
    while currentLayer <= numLayers:
        numBalls += count_layer(currentLayer)
        currentLayer += 1
    return numBalls

foo = int(raw_input("Enter number of layers: "))
print "There are " , count_pyramid(foo) , " balls in the triangular pyramid"