A140718 This is the beginning of a Prime Chain of 224 terms consisting of the output of 2x^2 +29 repeated four times, alternating with these same terms in reverse within a procedural expression of a single polynomial.

31, 31, 31, 31, 1597, 1597, 1597, 1597, 37, 37, 37, 37, 1487, 1487, 1487, 1487, 47, 47, 47, 47, 1381, 1381, 1381, 1381, 61, 61, 61, 61, 1279, 1279, 1279, 1279, 79, 79, 79, 79, 1181, 1181, 1181, 1181, 101, 101, 101, 101, 1087, 1087, 1087, 1087, 127, 127, 127