... Recently, Williams [4] employed his product-to-sum formula [3] in conjunction with conditions for the non-representability of integers by certain ternary quadratic forms to give ten eta quotients such that their Fourier coefficients vanish for all positive integers n in each of infinitely many non-overlapping arithmetic progressions. His main results can be stated as the following theorem: Theorem 1.1 For n, k ∈ N 0 , a 1 (2 2k+1 (8n + 5)) = a 2 (3 2k+1 (3n + 2)) = a 3 (3 2k (3n + 2)) = a 4 (3 2k+1 (6n + 5)) = a 5 (3 2k+1 (12n + 8)) = a 5 (3 2k+1 (12n + 11)) = a 7 (2 2k (8n + 7)) = a 8 (2 2k+1 (8n + 7)) = a 9 (3 2k+1 (3n + 2)) = a 10 (2 2k (8n + 7)) = 0, where the generating functions of the a i (n) are given by where ( j, a, b, c) ∈ { (1,2,4,4), (2,1,9,9), (3,1,9,9), (4,1,9,9), (5,1,9,9), (7,1,4,16), (8, 2, 4, 16), (9, 1, 9, 81), (10, 4, 4, 16)} and ( j, d, e) ∈ {(1, 16, 10), (2,9,6), (3,3,2), (4,9,6), (5,9,6), (7,8,7), (8,16,14), (9, 9, 6), (10, 4, 3), (10, 32, 28)}. ...