[рони]

orloff,

function d(num) {
            let arr = [...num.toString()];
            let len = arr.length - 2;
            let k = +arr[0] > 5 ? 10 : 5;
            k *= Math.pow(10, len);
            num = Math.ceil(num/k) * k;
            arr = [];
            for (let i = 0; i <= num; i += k) arr.push(i);
            return arr;
        }
        console.log(5,d(5));
        console.log(65,d(65));
        console.log(379,d(379));
        console.log(3469580,d(3469580));