A057869 Triangle of coefficients of x^2 in the Neumann polynomials.

1, 1, 4, 1, 24, 3, 192, 16, 1, 1920, 120, 5, 23040, 1152, 36, 1, 322560, 13440, 336, 7, 5160960, 184320, 3840, 64, 1, 92897280, 2903040, 51840, 720, 9, 1857945600, 51609600, 806400, 9600, 100, 1, 40874803200, 1021870080, 14192640, 147840