A048131 Becomes prime or 4 after exactly 9 iterations of f(x) = sum of prime factors of x.

4659, 5294, 5937, 9286, 10334, 10843, 15490, 16382, 17972, 18201, 18588, 18735, 19137, 19984, 20059, 22482, 23073, 23806, 25405, 26405, 26547, 27622, 27845, 28694, 28772, 30062, 30486, 31686, 32156, 32313, 33177, 33238, 33414, 33944