A072974 Numbers n such that C(3n,n)*2^n/(50n-6) is an integer.

15, 21, 27, 30, 51, 56, 57, 63, 69, 75, 84, 87, 89, 90, 99, 100, 102, 108, 111, 113, 123, 124, 129, 130, 132, 135, 138, 139, 153, 156, 159, 165, 166, 171, 183, 192, 195, 197, 201, 207, 210, 215, 216, 220, 221, 232, 246, 251, 258, 263, 264, 267, 273, 279, 283