A088728 p such that p^4 + q^4 = r^4 + s^4 = a(n).

158, 239, 292, 502, 542, 631, 1203, 1381, 2189, 2461, 2797, 2949, 3190, 3494, 3537, 4849, 4883, 5053, 6140, 6619, 6730, 6761, 7557, 7604, 8912, 8961, 9018, 9043, 9109, 9253, 9289, 9316, 9733, 10142, 10409, 10652, 11515, 12231, 12234, 12653, 13472