Let p be a prime number, and let n be a positive integer. Find the number of quadruples (a1,a2,a3,a4) with ai∈{0,1,…,pn−1} for i=1,2,3,4, such that pn∣(a1a2+a3a4+1). symmetryabstract algebramodular arithmeticnumber theory proposednumber theory