A059944 Denominators of Maclaurin series coefficients for 2 Cos[ x/Sqrt[ 3 ] + ArcTan[ - Sqrt[ 3 ] ] ] = Cos[ x/Sqrt[ 3 ] ] + Sqrt[ 3 ]Sin[ x/Sqrt[ 3 ] ].

1, 1, 6, 18, 216, 1080, 19440, 136080, 3265920, 29393280, 881798400, 9699782400, 349192166400, 4539498163200, 190658922854400, 2859883842816000, 137274424455168000, 2333665215737856000, 126017921649844224000