def isPentagonal(n): soln = quad_formula(3, -1, -2*n) if soln[0] > 0 and soln[0] == int(soln[0]) or soln[1] > 0 and soln[1] == int(soln[1]): return True else: return False
def isHexagonal(n): soln = quad_formula(2, -1, -n) if soln[0] > 0 and soln[0] == int(soln[0]) or soln[1] > 0 and soln[1] == int(soln[1]): return True else: return False
def isTriangular(n): soln = quad_formula(1, 1, -2*n) if soln[0] > 0 and soln[0] == int(soln[0]) or soln[1] > 0 and soln[1] == int(soln[1]): return True else: return False